diff --git a/lib/datasource.js b/lib/datasource.js
index 34f40e0b..1f3846c5 100644
--- a/lib/datasource.js
+++ b/lib/datasource.js
@@ -12,6 +12,7 @@ var EventEmitter = require('events').EventEmitter;
 var util = require('util');
 var assert = require('assert');
 var async = require('async');
+var traverse = require('traverse');
 
 if (process.env.DEBUG === 'loopback') {
   // For back-compatibility
@@ -396,12 +397,9 @@ DataSource.prototype.defineRelations = function (modelClass, relations) {
         // Check if the through model doesn't exist or resolved
         if (!throughModel || isModelDataSourceAttached(throughModel)) {
           // The target model is resolved
-          var params = {
-            foreignKey: relation.foreignKey,
-            as: name,
-            model: model,
-            options: relation.options
-          };
+          var params = traverse(relation).clone();
+          params.as = name;
+          params.model = model;
           if (throughModel) {
             params.through = throughModel;
           }
@@ -415,13 +413,10 @@ DataSource.prototype.defineRelations = function (modelClass, relations) {
       throughModel.once('dataSourceAttached', function (model) {
         if (isModelDataSourceAttached(targetModel)) {
           // The target model is resolved
-          var params = {
-            foreignKey: relation.foreignKey,
-            as: name,
-            model: targetModel,
-            through: model,
-            options: relation.options
-          };
+          var params = traverse(relations).clone();
+          params.as = name;
+          params.model = targetModel;
+          params.through = model;
           modelClass[relation.type].call(modelClass, name, params);
         }
       });
@@ -438,17 +433,14 @@ DataSource.prototype.defineRelations = function (modelClass, relations) {
       if (r.through) {
         throughModel = isModelClass(r.through) ? r.through : this.getModel(r.through, true);
       }
-      if (!isModelDataSourceAttached(targetModel) || (throughModel && !isModelDataSourceAttached(throughModel))) {
+      if ((!r.polymorphic && !isModelDataSourceAttached(targetModel)) || (throughModel && !isModelDataSourceAttached(throughModel))) {
         // Create a listener to defer the relation set up
         createListener(rn, r, targetModel, throughModel);
       } else {
         // The target model is resolved
-        var params = {
-          foreignKey: r.foreignKey,
-          as: rn,
-          model: targetModel,
-          options: r.options
-        };
+        var params = traverse(r).clone();
+        params.as = rn;
+        params.model = targetModel;
         if (throughModel) {
           params.through = throughModel;
         }