Issue with implementing OOB policy opcode fm_pymt_pol_pre_refund.c whose source code is not present

we are working on refund customization and want to implement fm_pymt_pol_pre_refund.c policy opcode to validate few checks before processing refund. Since this policy is not shipped by Oracle, we followed

approach suggested by Oracle in below link:

https://support.oracle.com/epmos/faces/DocumentDisplay?_afrLoop=488754098398271&id=1368774.1&_afrWindowMode=0&_adf.ctrl-state=1dvgko7owr_313

Steps i followed:

1. Created policy file for fm_pymt_pol_pre_refund.c opcode which is not present in OOB source code

2. Modified fm_pymt_pol_config.c to add entry for new policy as:

        { PCM_OP_PYMT_POL_PRE_REFUND,       "op_pymt_pol_pre_refund" },