Hi Vijay,
There will be one more mapping that will handle your fault message. In Receiver Interface you need to assign fault message type and one message Mapping for fault to source message type.
You can handle your fault response
Below is link for your reference.
http://scn.sap.com/people/shabarish.vijayakumar/blog/2006/11/02/fault-message-types--a-demo-part-1
Regards,
Rahul