diff --git a/lib/model/txproposal.js b/lib/model/txproposal.js
index e25331c..8935e8c 100644
--- a/lib/model/txproposal.js
+++ b/lib/model/txproposal.js
@@ -35,7 +35,9 @@ TxProposal._create.simple = function(txp, opts) {
 TxProposal._create.undefined = TxProposal._create.simple;
 
 TxProposal._create.multiple_outputs = function(txp, opts) {
-  txp.outputs = opts.outputs;
+  txp.outputs = _.map(opts.outputs, function(output) {
+    return _.pick(output, ['amount', 'toAddress', 'message']);
+  });
   txp.outputOrder = _.shuffle(_.range(txp.outputs.length + 1));
   try {
     txp.network = Bitcore.Address(txp.outputs[0].toAddress).toObject().network;
diff --git a/lib/server.js b/lib/server.js
index bdf7428..210e335 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -827,41 +827,28 @@ WalletService.prototype._canCreateTx = function(copayerId, cb) {
 WalletService.prototype.createTx = function(opts, cb) {
   var self = this;
 
-  if (!Utils.checkRequired(opts, ['proposalSignature']))
+  if (!opts.outputs) {
+    opts.outputs = _.pick(opts, ['amount', 'toAddress', 'message']);
+  }
+  opts.outputs = [].concat(opts.outputs);
+
+  if (!Utils.checkRequired(opts, ['outputs', 'proposalSignature']))
     return cb(new ClientError('Required argument missing'));
 
   opts.type = opts.type || Model.TxProposal.Types.SIMPLE;
   if (!Model.TxProposal.isTypeSupported(opts.type))
     return cb(new ClientError('Invalid proposal type'));
 
-  if (opts.type == Model.TxProposal.Types.MULTIPLEOUTPUTS) {
-    if (!Utils.checkRequired(opts, ['outputs']))
-      return cb(new ClientError('Required argument missing'));
-    _.each(opts.outputs, function(o) {
-      o.valid = true;
-      if (!Utils.checkRequired(o, ['toAddress', 'amount'])) {
-        o.valid = false;
-        cb(new ClientError('Required outputs argument missing'));
-        return false;
-      }
-      _.each(_.keys(o), function(key) {
-        if (!_.contains(['toAddress', 'amount', 'message', 'valid'], key)) {
-          o.valid = false;
-          cb(new ClientError('Invalid outputs argument found'));
-          return false;
-        }
-      });
-      if (!o.valid) return false;
-    });
-    if (_.any(opts.outputs, 'valid', false)) return;
-    _.each(opts.outputs, function(o) {
-      delete o.valid;
-    });
-
-  } else {
-    if (!Utils.checkRequired(opts, ['toAddress', 'amount']))
-      return cb(new ClientError('Required argument missing'));
-  }
+  _.each(opts.outputs, function(output) {
+    if (!Utils.checkRequired(output, ['toAddress', 'amount'])) {
+      output.valid = false;
+      cb(new ClientError('Required outputs argument missing'));
+      return false;
+    }
+  });
+  if (_.any(opts.outputs, {
+    valid: false
+  })) return;
 
   var feePerKb = opts.feePerKb || 10000;
   if (feePerKb < WalletUtils.MIN_FEE_PER_KB || feePerKb > WalletUtils.MAX_FEE_PER_KB)
@@ -878,17 +865,7 @@ WalletService.prototype.createTx = function(opts, cb) {
         if (!canCreate)
           return cb(new ClientError('NOTALLOWEDTOCREATETX', 'Cannot create TX proposal during backoff time'));
 
-        var copayer = wallet.getCopayer(self.copayerId);
-        var proposalHeader = Model.TxProposal.create(opts).getHeader();
-        var hash = WalletUtils.getProposalHash(proposalHeader);
-        if (!self._verifySignature(hash, opts.proposalSignature, copayer.requestPubKey))
-          return cb(new ClientError('Invalid proposal signature'));
-
-        var outputs = (opts.type == Model.TxProposal.Types.MULTIPLEOUTPUTS) ? opts.outputs : [{
-          toAddress: opts.toAddress,
-          amount: opts.amount
-        }];
-        _.each(outputs, function(output) {
+        _.each(opts.outputs, function(output) {
           output.valid = false;
           var toAddress = {};
           try {
@@ -901,7 +878,7 @@ WalletService.prototype.createTx = function(opts, cb) {
             cb(new ClientError('INVALIDADDRESS', 'Incorrect address network'));
             return false;
           }
-          if (output.amount <= 0) {
+          if (!_.isNumber(output.amount) || _.isNaN(output.amount) || output.amount <= 0) {
             cb(new ClientError('Invalid amount'));
             return false;
           }
@@ -911,9 +888,9 @@ WalletService.prototype.createTx = function(opts, cb) {
           }
           output.valid = true;
         });
-        if (_.any(outputs, 'valid', false)) return;
-
-        var changeAddress = wallet.createAddress(true);
+        if (_.any(opts.outputs, {
+          valid: false
+        })) return;
 
         var txp = Model.TxProposal.create({
           type: opts.type,
@@ -926,18 +903,23 @@ WalletService.prototype.createTx = function(opts, cb) {
           proposalSignature: opts.proposalSignature,
           feePerKb: feePerKb,
           payProUrl: opts.payProUrl,
-          changeAddress: changeAddress,
           requiredSignatures: wallet.m,
           requiredRejections: Math.min(wallet.m, wallet.n - wallet.m + 1),
         });
 
+        var copayer = wallet.getCopayer(self.copayerId);
+        var hash = WalletUtils.getProposalHash(txp.getHeader());
+        if (!self._verifySignature(hash, opts.proposalSignature, copayer.requestPubKey))
+          return cb(new ClientError('Invalid proposal signature'));
+
+        txp.changeAddress = wallet.createAddress(true);
 
         self._selectTxInputs(txp, function(err) {
           if (err) return cb(err);
 
           $.checkState(txp.inputs);
 
-          self.storage.storeAddressAndWallet(wallet, changeAddress, function(err) {
+          self.storage.storeAddressAndWallet(wallet, txp.changeAddress, function(err) {
             if (err) return cb(err);
 
             self.storage.storeTx(wallet.id, txp, function(err) {
diff --git a/test/integration/server.js b/test/integration/server.js
index 4a17ccb..e65d6d0 100644
--- a/test/integration/server.js
+++ b/test/integration/server.js
@@ -137,7 +137,7 @@ helpers.toSatoshi = function(btc) {
 helpers.stubUtxos = function(server, wallet, amounts, cb) {
   var amounts = [].concat(amounts);
 
-  async.map(_.range(1, Math.ceil(amounts.length / 2) + 1), function(i, next) {
+  async.mapSeries(_.range(1, Math.ceil(amounts.length / 2) + 1), function(i, next) {
     server.createAddress({}, function(err, address) {
       next(err, address);
     });
@@ -248,7 +248,7 @@ helpers.createAddresses = function(server, wallet, main, change, cb) {
 
 var storage, blockchainExplorer;
 
-var useMongo = false;
+var useMongo = true;
 
 function initStorage(cb) {
   function getDb(cb) {
@@ -1685,13 +1685,11 @@ describe('Wallet service', function() {
       });
     });
 
-    it('should fail to create tx for type multiple_outputs with invalid output argument', function(done) {
+    it('should fail to create tx for type multiple_outputs with missing output argument', function(done) {
       helpers.stubUtxos(server, wallet, [100, 200], function() {
         var outputs = [{
-          toAddress: '18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7',
           amount: 80,
           message: 'message #1',
-          foo: 'bar'
         }, {
           toAddress: '18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7',
           amount: 90,
@@ -1700,7 +1698,7 @@ describe('Wallet service', function() {
         var txOpts = helpers.createProposalOptsByType(Model.TxProposal.Types.MULTIPLEOUTPUTS, outputs, 'some message', TestData.copayers[0].privKey_1H_0);
         server.createTx(txOpts, function(err, tx) {
           should.exist(err);
-          err.message.should.contain('Invalid outputs argument');
+          err.message.should.contain('outputs argument missing');
           done();
         });
       });
diff --git a/test/models/txproposal.js b/test/models/txproposal.js
index 32f6935..49e7430 100644
--- a/test/models/txproposal.js
+++ b/test/models/txproposal.js
@@ -64,18 +64,11 @@ describe('TXProposal', function() {
   });
 
   describe('#getHeader', function() {
-    it('should be compatible with simple proposal legacy header', function() {
-      var x = TxProposal.fromObj(aTXP());
-      var proposalHeader = x.getHeader();
-      var pH = WalletUtils.getProposalHash.apply(WalletUtils, proposalHeader);
-      var uH = WalletUtils.getProposalHash(x.toAddress, x.amount, x.message, x.payProUrl);
-      pH.should.equal(uH);
-    });
     it('should handle multiple-outputs', function() {
       var x = TxProposal.fromObj(aTXP(TxProposal.Types.MULTIPLEOUTPUTS));
       var proposalHeader = x.getHeader();
       should.exist(proposalHeader);
-      var pH = WalletUtils.getProposalHash.apply(WalletUtils, proposalHeader);
+      var pH = WalletUtils.getProposalHash(proposalHeader);
       should.exist(pH);
     });
   });