Look for program names defined as constants in RFITEMAR (there are some including 'RFITEMAR' itself) and replace the standard names with your copy names. Also perform some where-used search on those constants to identify some form like fill_kdf_callback which use those constants)
For information, which request required the duplication of the standard program, while SAP has provided BTE / BADI to adapt it. ?
Regards,
Raymond