Adding Custom fields to standard SAP-EBP application

Hi,

A functionality requires some custom fields to be added to the standard SAP-SRM EBP ( Manage business partners) application.

If I copy the whole BBP_VENDOR_CREATE program into a Z-program, and the BBPMAININT internet service to a Z-application, then would it be feasible??

Which is the best way to add custom fields in a SAP standard EBP application--in the 'Manage business partners' section.

Regards,

Goutam