Hi Vinita,
Please check the below link for the Xi interfaces used for transfering the PR from ECC to SRM.
Interfaces used in the MM-SUS scenario - Supplier Relationship Management - SCN Wiki\http://wiki.scn.sap.com/wiki/display/SRM/Interfaces+used+in+the+MM-SUS+scenario
Also got throught this link which tells about the configuration needs to be done in the system
I hope it will help you....
In case if you need further help please revert back ..
Regards,
Rahul