Try to maintain BC

lib/associations/belongs-to.js

@@ -39,7 +39,7 @@ module.exports = (function() {
       , keyType        = ((this.target.hasPrimaryKeys && targetKeys.length === 1) ? this.target.rawAttributes[targetKeys[0]].type : DataTypes.INTEGER)
 
     this.identifier = this.options.foreignKey || Utils._.underscoredIf(Utils.singularize(this.target.tableName, this.target.options.language) + "Id", this.source.options.underscored)
-    //this.identifier = this.options.foreignKey || Utils._.underscoredIf(this.as + "Id", this.source.options.underscored)
+
     newAttributes[this.identifier] = { type: this.options.keyType || keyType }
     Helpers.addForeignKeyConstraints(newAttributes[this.identifier], this.target, this.source, this.options)
     Utils._.defaults(this.source.rawAttributes, newAttributes)

lib/dialects/abstract/query-generator.js

@@ -700,16 +700,16 @@ module.exports = (function() {
 
       for (var key in hash) {
         var value = hash[key]
+          ,  _key
+          , _value = null
 
         if(this.isAssociationFilter(key, dao)){
-          key = this.getAssociationFilterColumn(key, dao);
+          _key = key = this.getAssociationFilterColumn(key, dao);
         } else {
-          key = this.quoteIdentifiers(key)
+          _key = this.quoteIdentifiers(key)
         }
 
          //handle qualified key names
-        var _key   = key
-          , _value = null
 
         if (Array.isArray(value)) {
           result.push(this.arrayValue(value, key, _key, dao))

test/include.test.js

@@ -748,8 +748,8 @@ describe(Support.getTestDialectTeaser("Include"), function () {
         , Item = this.sequelize.define('Item', {'test': DataTypes.STRING})
         , Order = this.sequelize.define('Order', {'position': DataTypes.INTEGER})
 
-      User.belongsTo(Item, {'as': 'itemA'})
-      User.belongsTo(Item, {'as': 'itemB'})
+      User.belongsTo(Item, {'as': 'itemA', foreignKey: 'itemA_id'})
+      User.belongsTo(Item, {'as': 'itemB', foreignKey: 'itemB_id'})
       User.belongsTo(Order)
 
       this.sequelize.sync().done(function() {