Vivek,
Make sure you didn't accidentally pick "Update Client Key Property".
You need to make sure that you are defining and setting _returnData in your edit steplet to point to an array of your object types. For example:
Order[] _returnData;
_returnData = handler.replaceOrders();
Also, make sure all your POJO properties have Public visibility or Agentry wont be able to map them back.
Jason Latko - Senior Product Developer at SAP