diff --git a/README.md b/README.md
index de7b466..4802d4e 100644
--- a/README.md
+++ b/README.md
@@ -130,54 +130,53 @@ var bitcore = require('bitcore');
 var networks = bitcore.networks;
 var Peer = bitcore.Peer;
 var Transaction = bitcore.Transaction;
-var Address = bitcore.Address;
-var Script = bitcore.Script;
-var coinUtil = bitcore.util;
 var PeerManager = require('soop').load('../PeerManager', {
   network: networks.testnet
 });
 
-var createTx = function() {
-  var TXIN = 'd05f35e0bbc495f6dcab03e599c8f5e32a07cdb4bc76964de201d06a2a7d8265';
-  var TXIN_N = 0;
-  var ADDR = 'muHct3YZ9Nd5Pq7uLYYhXRAxeW4EnpcaLz';
-  var VAL = '0.001';
-
-  var txobj = {
-    version: 1,
-    lock_time: 0,
-    ins: [],
-    outs: []
-  };
-
-  var txin = {
-    s: coinUtil.EMPTY_BUFFER, // Add signature
-    q: 0xffffffff
-  };
-
-  var hash = new Buffer(TXIN.split('').reverse(), 'hex');
-  var vout = parseInt(TXIN_N);
-  var voutBuf = new Buffer(4);
-
-  voutBuf.writeUInt32LE(vout, 0);
-  txin.o = Buffer.concat([hash, voutBuf]);
-  txobj.ins.push(txin);
-
-  var addr = new Address(ADDR);
-  var script = Script.createPubKeyHashOut(addr.payload());
-  var valueNum = coinUtil.parseValue(VAL);
-  var value = coinUtil.bigIntToValue(valueNum);
-
-  var txout = {
-    v: value,
-    s: script.getBuffer(),
-  };
-  txobj.outs.push(txout);
-
-  return new Transaction(txobj);
+// this can be get from insight.bitcore.io API o blockchain.info
+var utxos = { 
+  "unspent": [
+    {
+      "address": "n4g2TFaQo8UgedwpkYdcQFF6xE2Ei9Czvy",
+      "txid": "2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc1",
+      "scriptPubKey": "76a914fe021bac469a5c49915b2a8ffa7390a9ce5580f988ac",
+      "vout": 1,
+      "amount": 1.0101,
+      "confirmations":7
+    },
+    {
+      "address": "mhNCT9TwZAGF1tLPpZdqfkTmtBkY282YDW",
+      "txid": "2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc2",
+      "scriptPubKey": "76a9141448534cb1a1ec44665b0eb2326e570814afe3f188ac",
+      "vout": 0,
+      "confirmations": 1,
+      "amount": 10
+    },
+};
+
+//private keys in WIF format (see Transaction.js for other options)
+var keys = [
+  "cSq7yo4fvsbMyWVN945VUGUWMaSazZPWqBVJZyoGsHmNq6W4HVBV",
+  "cPa87VgwZfowGZYaEenoQeJgRfKW6PhZ1R65EHTkN1K19cSvc92G",
+  "cPQ9DSbBRLva9av5nqeF5AGrh3dsdW8p2E5jS4P8bDWZAoQTeeKB"
+];
 
+function createTx() {
+  var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
+
+  var ret = Transaction.createAndSign(utxos, outs, keys); 
+
+  / * create and signing can be done in 2 steps using:
+    *       var ret = Transaction.create(utxos,outs);
+    * and later:
+    *       ret.tx.sign(ret.tx.selectedUtxos, outs, keys); 
+    */
+
+  return ret.tx.serialize().toString('hex');
 };
 
+
 var peerman = new PeerManager();
 peerman.addPeer(new Peer('127.0.0.1', 18333));
 
diff --git a/Transaction.js b/Transaction.js
index f9c8e69..6d28741 100644
--- a/Transaction.js
+++ b/Transaction.js
@@ -778,10 +778,16 @@ Transaction._sumOutputs = function(outs) {
   return valueOutSat;
 }
 
-Transaction.prepare = function (ins, outs, opts) {
+/*
+ * createWithFee 
+ *  Create a TX given ins (selected already), outs, and a FIXED fee
+ *  details on the input on .create
+ */
+
+Transaction.createWithFee = function (ins, outs, feeSat, opts) {
   opts = opts || {};
+  feeSat = feeSat ||  0;
 
-  var feeSat = opts.feeSat || (opts.fee? util.parseValue(opts.fee) : FEE_PER_1000B_SAT );
   var txobj = {};
   txobj.version = 1;
   txobj.lock_time = opts.lockTime || 0;
@@ -981,18 +987,74 @@ Transaction.prototype.sign = function (selectedUtxos, keys, opts) {
     self.ins[i].s = scriptSig.getBuffer();
     inputSigned++;
   }
-
   var complete = inputSigned === l;
-
   return complete;
 };
 
+/*
+ * create
+ *
+ *  creates a transaction without signing it.
+ *
+ *   @utxos
+ *   @outs
+ *   @opts
+ *
+ *  See createAndSign for documentation on the inputs
+ *
+ *   Returns:
+ *     { tx: {}, selectedUtxos: []}
+ *   see createAndSign for details
+ *
+ */
+
+Transaction.create = function (utxos, outs, opts) {
 
+    //starting size estimation
+    var size    = 500;
+    var opts    = opts || {};
 
+    var givenFeeSat;
+    if (opts.fee || opts.feeSat) {
+      givenFeeSat = opts.fee ? opts.fee * util.COIN : opts.feeSat;
+    }
+
+    var selectedUtxos;
+    do {
+      // based on https://en.bitcoin.it/wiki/Transaction_fees
+      maxSizeK     = parseInt(size/1000) + 1;
+      var feeSat  = givenFeeSat
+        ? givenFeeSat : maxSizeK * FEE_PER_1000B_SAT ;
+
+      var valueOutSat = Transaction
+        ._sumOutputs(outs)
+        .add(feeSat);
+
+      selectedUtxos = Transaction
+        .selectUnspent(utxos,valueOutSat / util.COIN, opts.allowUnconfirmed);
+
+      if (!selectedUtxos) {
+        throw new Error(
+          'the given UTXOs dont sum up the given outputs: ' 
+          + valueOutSat.toString() 
+          + ' (fee is ' + feeSat
+          + ' )SAT'
+        );
+      }
+      var tx = Transaction.createWithFee(selectedUtxos, outs, feeSat, {
+        remainderAddress: opts.remainderAddress,
+        lockTime: opts.lockTime,
+      });
+
+      size = tx.getSize();
+    } while (size > (maxSizeK+1)*1000 );
+
+    return {tx: tx, selectedUtxos: selectedUtxos};
+};
 
 
 /*
- * create
+ * createAndSign
  *
  *  creates and signs a transaction
  *
@@ -1031,66 +1093,33 @@ Transaction.prototype.sign = function (selectedUtxos, keys, opts) {
  *      signhash: SIGHASH_ALL
  *    }
  *
+ *
+ *   Retuns:
+ *   { 
+ *      tx: The new created transaction,
+ *      selectedUtxos: The UTXOs selected as inputs for this transaction
+ *   }
+ *
  *  Amounts are in BTC. instead of fee and amount; feeSat and amountSat can be given, 
  *  repectively, to provide amounts in satoshis.
  *
- *  If no remainderAddress is given, and there is a remainderAddress
- *  first in address will be used. (TODO: is this is reasonable?)
+ *  If no remainderAddress is given, and there are remainder coins, the
+ *  first IN address will be used to return the coins. (TODO: is this is reasonable?)
  *
- *  if not keys are provided, the transaction will no be signed. .sign can be used to
- *  sign it later.
- *
- *  The Transaction creation is handled in 3 steps:
- *    .selectUnspent
- *    .prepare
+ *  The Transaction creation is handled in 2 steps:
+ *    .create
+ *      .selectUnspent
+ *      .createWithFee
  *    .sign
  *
+ *  If you need just to create a TX and not sign it, use .create  
+ *
  */
 
-
-Transaction.create = function (utxos, outs, keys, opts) {
-
-    //starting size estimation
-    var size    = 500;
-    var opts    = opts || {};
-
-    var givenFeeSat;
-    if (opts.fee || opts.feeSat) {
-      givenFeeSat = opts.fee ? opts.fee * util.COIN : opts.feeSat;
-    }
-
-    do {
-      // based on https://en.bitcoin.it/wiki/Transaction_fees
-      maxSizeK     = parseInt(size/1000) + 1;
-      var feeSat  = givenFeeSat
-        ? givenFeeSat : maxSizeK * FEE_PER_1000B_SAT ;
-
-      var valueOutSat = Transaction
-        ._sumOutputs(outs)
-        .add(feeSat);
-
-      var selectedUtxos = Transaction
-        .selectUnspent(utxos,valueOutSat / util.COIN, opts.allowUnconfirmed);
-
-      if (!selectedUtxos) {
-        throw new Error(
-          'the given UTXOs dont sum up the given outputs: ' 
-          + valueOutSat.toString() 
-          + ' (fee is ' + feeSat
-          + ' )SAT'
-        );
-      }
-      var tx = Transaction.prepare(selectedUtxos, outs, {
-        feeSat: feeSat,
-        remainderAddress: opts.remainderAddress,
-        lockTime: opts.lockTime,
-      });
-
-      size = tx.getSize();
-    } while (size > (maxSizeK+1)*1000 );
-
-    if (keys) tx.sign(selectedUtxos, keys);
-    return tx;
+Transaction.createAndSign = function (utxos, outs, keys, opts) {
+    var ret = Transaction.create(utxos, outs, opts);
+    ret.tx.sign(ret.selectedUtxos, keys);
+    return ret;
 };
 
 var TransactionInputsCache = exports.TransactionInputsCache =
diff --git a/examples/CreateAndSignTx.js b/examples/CreateAndSignTx.js
index aa8a746..0e34252 100644
--- a/examples/CreateAndSignTx.js
+++ b/examples/CreateAndSignTx.js
@@ -8,195 +8,34 @@ var run = function() {
   var amt     = '0.005';
   var toAddress = 'myuAQcCc1REUgXGsCTiYhZvPPc3XxZ36G1';
   var changeAddressString = 'moDz3jEo9q7CxjBDjmb13sL4SKkgo2AACE';
-  var feeString = '0.0001';
 
-  var safeUnspent = [
-  {
-  address: "mqSjTad2TKbPcKQ3Jq4kgCkKatyN44UMgZ",
-  hash: "2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc1",
-  vout: 1,
-  ts: 1394719301,
-  scriptPubKey: "76a9146ce4e1163eb18939b1440c42844d5f0261c0338288ac",
-  amount: 0.01,
-  confirmations: 2
-  }
-  ]
-  ;
-
-  console.log('TX Data: BTC:' + amt + ' => '+ toAddress + ', change To:' + changeAddressString ) ;
-  console.log('Unspends:', safeUnspent);
-
-  var wk  = new bitcore.WalletKey({
-    network: bitcore.networks.testnet
-  });
-  wk.fromObj({ priv: priv, });
-
-  var wkObj= wk.storeObj();
-  var keyPairs = [{
-    key: wkObj.priv,
-    address: wkObj.addr,
+  var utxos = [{
+    address: "mqSjTad2TKbPcKQ3Jq4kgCkKatyN44UMgZ",
+    txid: "2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc1",
+    vout: 1,
+    ts: 1394719301,
+    scriptPubKey: "76a9146ce4e1163eb18939b1440c42844d5f0261c0338288ac",
+    amount: 0.01,
+    confirmations: 2
   }];
-  console.log('KEY DB IS:', keyPairs); 
-
-  var Address = bitcore.Address;
-  var Transaction = bitcore.Transaction;
-  var Script = bitcore.Script;
-  var nets = bitcore.networks;
-  var z = bitcore.bignum(0);
-  var amt = bitcore.util.parseValue(amt);
-
-  if(z.cmp(amt) === 0 )
-    throw "spend amount must be greater than zero";
-
-  if(!changeAddressString)
-    throw "change address was not provided";
-
-  var fee = bitcore.util.parseValue(feeString || '0');
-  var total = bitcore.bignum(0).add(amt).add(fee);
-  var address = new Address(toAddress);
-  var sendTx = new Transaction();
-  var i;
-
-  var unspent = [];
-  var unspentAmt = bitcore.bignum(0);
-
-
-  for(i=0;i<safeUnspent.length;i++) {
-    unspent.push(safeUnspent[i]);
-
-        var amountSatoshiString = new bitcore.bignum(safeUnspent[i].amount * Math.pow(10,8)).toString();
-
-        unspentAmt = unspentAmt.add(new bitcore.bignum(amountSatoshiString));
-
-        // If > -1, we have enough to send the requested amount
-        if(unspentAmt.cmp(total) > -1) {
-          break;
-        }
-      }
-
-      if(unspentAmt.cmp(total) < 0) {
-        throw "you do not have enough bitcoins to send this amount";
-      }
-
-      var txobj = {};
-      txobj.version = 1;
-      txobj.lock_time = 0;
-      txobj.ins = [];
-      txobj.outs = [];
-      
-      for(i=0;i<unspent.length;i++) {
-        var txin = {};
-
-        txin.s = bitcore.util.EMPTY_BUFFER;
-        txin.q = 0xffffffff;
 
-        var hash = new bitcore.Buffer(unspent[i].hash, 'hex');
-        var hashReversed = bitcore.buffertools.reverse(hash);
-        var vout = parseInt(unspent[i].vout);
-        var voutBuf = new bitcore.Buffer(4);
-        voutBuf.writeUInt32LE(vout, 0);
-
-        txin.o = bitcore.Buffer.concat([hashReversed, voutBuf]);
-        txobj.ins.push(txin); 
-      }
-
-
-      // This is not used really, but we keep it for the future.
-      var version = address.version();
-      var script;
-      if (version == nets.livenet.addressPubkey || version == nets.testnet.addressPubkey)
-        script = Script.createPubKeyHashOut(address.payload());
-      else if (version == nets.livenet.addressScript || version == nets.testnet.addressScript)
-        script = Script.createP2SH(address.payload());
-      else
-        throw new Error('invalid output address');
-
-      var value = bitcore.util.bigIntToValue(amt);
-      var txout = {
-        v: value,
-        s: script.getBuffer(),
-      };
-      txobj.outs.push(txout);
-      var remainder = unspentAmt.sub(total);
-
-      if(z.cmp(amt) !== 0 ) {
-        var changeAddress = new Address(changeAddressString);
-        var changeValue = bitcore.util.bigIntToValue(remainder);
-
-        // This is not used really, but we keep it for the future.
-        var cversion = changeAddress.version();
-        var cscript;
-        if (cversion == nets.livenet.addressPubkey || cversion == nets.testnet.addressPubkey)
-          cscript = Script.createPubKeyHashOut(changeAddress.payload());
-        else if (cversion == nets.livenet.addressScript || cversion == nets.testnet.addressScript)
-          cscript = Script.createP2SH(changeAddress.payload());
-        else
-          throw new Error('invalid change output address');
-
-        var change = {
-          v: changeValue,
-          s: cscript.getBuffer(),
-        };
-        txobj.outs.push(change);
-      }
-
-      var tx = new Transaction(txobj);
-      var anypay = false;
-      var l = unspent.length;
-      var allFound = l;
-
-      // Here will be the beginning of your signing for loop
-      for(i=0;i < l;i++) {
-        var scriptBuf = new bitcore.Buffer(unspent[i].scriptPubKey, 'hex');
-
-        var s = new Script(scriptBuf);
-        if (s.classify() !==  Script.TX_PUBKEYHASH) {
-          throw new Error('input script type '+ s.getRawOutType() +' not supported yet');
-        }
-        var txSigHash = tx.hashForSignature(s, i,
-                  anypay ? Transaction.SIGHASH_ANYONECANPAY : Transaction.SIGHASH_ALL);
-
-
-  //      txSigHash = bitcore.buffertools.reverse(txSigHash);
-
-        for(var j=0;j<keyPairs.length;j++) {
-          var kp = keyPairs[j];
-          if(kp.address === unspent[i].address) {
-            console.log('SIGNING With...', kp.key); //TODO
-            console.log('HASH TO SIGN: ',bitcore.buffertools.toHex(txSigHash)); //TODO
-            var wKey = new bitcore.WalletKey({network: bitcore.networks.testnet});
-            wKey.fromObj({
-              priv: kp.key,
-            });
-
-            console.log('PRIV KEY', bitcore.buffertools.toHex(wKey.privKey.private )); //TODO
-            console.log('PUB KEY', bitcore.buffertools.toHex(wKey.privKey.public )); //TODO
-
-            var sigRaw = wKey.privKey.signSync(txSigHash);
-            console.log('SIGNATURE: ',bitcore.buffertools.toHex(sigRaw)); //TODO
+  console.log('TX Data: BTC:' + amt + ' => '+ toAddress + ', change To:' + changeAddressString ) ;
+  console.log('Unspends Outputs:', utxos);
 
-            console.log('VERIFY: ',wKey.privKey.verifySignatureSync(txSigHash, sigRaw)); //TODO
 
-            var sigType = new bitcore.Buffer(1);
-            sigType[0] = anypay ? Transaction.SIGHASH_ANYONECANPAY : Transaction.SIGHASH_ALL;
-            var sig = bitcore.Buffer.concat([sigRaw, sigType]);
+  var outs = [{address:toAddress, amount:amt}];
+  var keys = [priv];
 
-            var scriptSig = new Script();
-            scriptSig.chunks.push(sig);
-            scriptSig.chunks.push(wKey.privKey.public);
-            scriptSig.updateBuffer();
-            tx.ins[i].s = scriptSig.getBuffer();
-            allFound--;
-            break;
-          }
-        }
-      }
+  var ret = bitcore.Transaction.createAndSign(utxos, outs, keys,
+                {remainderAddress: changeAddressString}); 
 
-      if (allFound !== 0)  {
-        throw new Error('could not find priv key for some inputs');
-      }
+   /* create and signing can be done in 2 steps using:
+    *       var ret = Transaction.create(utxos,outs);
+    * and later:
+    *       ret.tx.sign(ret.tx.selectedUtxos, outs, keys); 
+    */
 
-  var txHex = tx.serialize().toString('hex');
+  var txHex =  ret.tx.serialize().toString('hex');
   console.log('TX HEX IS: ', txHex);
 };
 
diff --git a/test/test.Transaction.js b/test/test.Transaction.js
index 6de6b26..094dd0b 100644
--- a/test/test.Transaction.js
+++ b/test/test.Transaction.js
@@ -86,8 +86,13 @@ describe('Transaction', function() {
   it('#create should be able to create instance', function() {
     var utxos =testdata.dataUnspent;
     var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
-    var tx = Transaction.create(utxos, outs, null, opts);
-    should.exist(tx);
+
+    var ret = Transaction.create(utxos, outs, opts);
+    should.exist(ret.tx);
+    should.exist(ret.selectedUtxos);
+    ret.selectedUtxos.length.should.equal(2);
+
+    var tx = ret.tx;
 
     tx.version.should.equal(1);
     tx.ins.length.should.equal(2);
@@ -105,11 +110,11 @@ describe('Transaction', function() {
     var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:80}];
     Transaction
       .create
-      .bind(utxos, outs, null, opts)
+      .bind(utxos, outs, opts)
       .should.throw();
 
     var outs2 = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.5}];
-    should.exist( Transaction.create(utxos, outs2, null, opts));
+    should.exist( Transaction.create(utxos, outs2, opts));
 
     // do not allow unconfirmed
     Transaction.create.bind(utxos, outs2).should.throw();
@@ -119,66 +124,96 @@ describe('Transaction', function() {
   it('#create should create same output as bitcoind createrawtransaction ', function() {
     var utxos =testdata.dataUnspent;
     var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
-    var tx = Transaction.create(utxos, outs, null, opts); 
-
+    var ret = Transaction.create(utxos, outs, opts); 
+    var tx = ret.tx;
 
     // string output generated from: bitcoind createrawtransaction '[{"txid": "2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc1","vout":1},{"txid":"2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc2","vout":0}  ]' '{"mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE":0.08,"mwZabyZXg8JzUtFX1pkGygsMJjnuqiNhgd":0.0299}'
     tx.serialize().toString('hex').should.equal('0100000002c1cf12ab89729d19d3cdec8ae531b5038d56c741006a105d532b3a7afa65c12a0100000000ffffffffc2cf12ab89729d19d3cdec8ae531b5038d56c741006a105d532b3a7afa65c12a0000000000ffffffff0200127a00000000001976a914774e603bafb717bd3f070e68bbcccfd907c77d1388acb09f2d00000000001976a914b00127584485a7cff0949ef0f6bc5575f06ce00d88ac00000000');
 
+  });
+
+  it('#create should create same output as bitcoind createrawtransaction wo remainder', function() {
+    var utxos =testdata.dataUnspent;
     // no remainder
-    outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
-    tx = Transaction.create(utxos, outs, null, {fee:0.03} ); 
+    var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
+    var ret = Transaction.create(utxos, outs, {fee:0.03} ); 
+    var tx = ret.tx;
 
     // string output generated from: bitcoind createrawtransaction '[{"txid": "2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc1","vout":1},{"txid":"2ac165fa7a3a2b535d106a0041c7568d03b531e58aeccdd3199d7289ab12cfc2","vout":0}  ]' '{"mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE":0.08}'
     //
     tx.serialize().toString('hex').should.equal('0100000002c1cf12ab89729d19d3cdec8ae531b5038d56c741006a105d532b3a7afa65c12a0100000000ffffffffc2cf12ab89729d19d3cdec8ae531b5038d56c741006a105d532b3a7afa65c12a0000000000ffffffff0100127a00000000001976a914774e603bafb717bd3f070e68bbcccfd907c77d1388ac00000000');
   });
  
-  it('#sign should sign a tx', function() {
+  it('#createAndSign should sign a tx', function() {
     var utxos =testdata.dataUnspentSign.unspent;
     var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
-    var tx = Transaction.create(utxos, outs, testdata.dataUnspentSign.keyStrings, opts); 
+    var ret = Transaction.createAndSign(utxos, outs, testdata.dataUnspentSign.keyStrings, opts); 
+    var tx = ret.tx;
     tx.isComplete().should.equal(true);
     tx.ins.length.should.equal(1);
     tx.outs.length.should.equal(2);
 
     var outs2 = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:16}];
-    var tx2 = Transaction.create(utxos, outs2, testdata.dataUnspentSign.keyStrings, opts); 
+    var ret2 = Transaction.createAndSign(utxos, outs2, testdata.dataUnspentSign.keyStrings, opts); 
+    var tx2 = ret2.tx;
     tx2.isComplete().should.equal(true);
     tx2.ins.length.should.equal(3);
     tx2.outs.length.should.equal(2);
   });
 
-  it('#sign should sign an incomplete tx ', function() {
+  it('#createAndSign should sign an incomplete tx ', function() {
     var keys = ['cNpW8B7XPAzCdRR9RBWxZeveSNy3meXgHD8GuhcqUyDuy8ptCDzJ'];
     var utxos =testdata.dataUnspentSign.unspent;
     var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
-    var tx = Transaction.create(utxos, outs, keys, opts); 
+    var ret = Transaction.createAndSign(utxos, outs, keys, opts); 
+    var tx = ret.tx;
     tx.ins.length.should.equal(1);
     tx.outs.length.should.equal(2);
-    tx.isComplete().should.equal(false);
   });
-  it('#sign should sign a tx in multiple steps', function() {
-    var utxos = Transaction.selectUnspent(testdata.dataUnspentSign.unspent,13, true);
+  it('#isComplete should return TX signature status', function() {
+    var keys = ['cNpW8B7XPAzCdRR9RBWxZeveSNy3meXgHD8GuhcqUyDuy8ptCDzJ'];
+    var utxos =testdata.dataUnspentSign.unspent;
     var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.08}];
+    var ret = Transaction.createAndSign(utxos, outs, keys, opts); 
+    var tx = ret.tx;
+    tx.isComplete().should.equal(false);
+    tx.sign(ret.selectedUtxos, testdata.dataUnspentSign.keyStrings);
+    tx.isComplete().should.equal(true);
+  });
+
+  it('#sign should sign a tx in multiple steps (case1)', function() {
+    var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:1.08}];
+    var ret = Transaction.create(testdata.dataUnspentSign.unspent, outs, opts); 
+    var tx            = ret.tx;
+    var selectedUtxos = ret.selectedUtxos;
 
-    var tx = Transaction.prepare(utxos, outs, opts); 
     var k1 = testdata.dataUnspentSign.keyStrings.slice(0,1);
+
+    tx.isComplete().should.equal(false);
+
+    tx.sign(selectedUtxos, k1).should.equal(false);
+
     var k23 = testdata.dataUnspentSign.keyStrings.slice(1,3);
-    tx.sign(utxos, k1).should.equal(false);
-    tx.sign(utxos, k23).should.equal(true);
+    tx.sign(selectedUtxos, k23).should.equal(true);
+    tx.isComplete().should.equal(true);
+  });
+
+  it('#sign should sign a tx in multiple steps (case2)', function() {
+    var outs = [{address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:16}];
+    var ret = Transaction.create(testdata.dataUnspentSign.unspent, outs, opts); 
+    var tx            = ret.tx;
+    var selectedUtxos = ret.selectedUtxos;
 
-    var tx2 = Transaction.prepare(utxos, outs, opts); 
     var k1 = testdata.dataUnspentSign.keyStrings.slice(0,1);
     var k2 = testdata.dataUnspentSign.keyStrings.slice(1,2);
     var k3 = testdata.dataUnspentSign.keyStrings.slice(2,3);
-    tx2.sign(utxos, k1).should.equal(false);
-    tx2.sign(utxos, k2).should.equal(false);
-    tx2.sign(utxos, k3).should.equal(true);
+    tx.sign(selectedUtxos, k1).should.equal(false);
+    tx.sign(selectedUtxos, k2).should.equal(false);
+    tx.sign(selectedUtxos, k3).should.equal(true);
  
   });
 
-  it('#create: should generate dynamic fee and readjust (and not) the selected UTXOs', function() {
+  it('#createAndSign: should generate dynamic fee and readjust (and not) the selected UTXOs', function() {
     //this cases exceeds the input by 1mbtc AFTEr calculating the dynamic fee,
     //so, it should trigger adding a new 10BTC utxo
     var utxos =testdata.dataUnspentSign.unspent;
@@ -188,7 +223,8 @@ describe('Transaction', function() {
       outs.push({address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.01});
     }
 
-    var tx = Transaction.create(utxos, outs, testdata.dataUnspentSign.keyStrings, opts); 
+    var ret = Transaction.createAndSign(utxos, outs, testdata.dataUnspentSign.keyStrings, opts); 
+    var tx = ret.tx;
     tx.getSize().should.equal(3560);
 
     // ins = 11.0101 BTC (2 inputs: 1.0101 + 10 );
@@ -209,7 +245,8 @@ describe('Transaction', function() {
       outs.push({address:'mrPnbY1yKDBsdgbHbS7kJ8GVm8F66hWHLE', amount:0.01});
     }
 
-    var tx = Transaction.create(utxos, outs, testdata.dataUnspentSign.keyStrings, opts); 
+    var ret = Transaction.createAndSign(utxos, outs, testdata.dataUnspentSign.keyStrings, opts); 
+    var tx = ret.tx;
     tx.getSize().should.equal(3485);
 
     // ins = 1.0101 BTC (1 inputs: 1.0101);