R12 PPR Check Printing

Hi,

   We are currently in process of implementing Oracle Payments in R12. We have a requirement to add additional XML tags to SEPA format.

    I understand we need to add custom code logic in IBY_FD_EXTRACT_EXT_PUB to fulfill our requirement.

   Question I have is,

    1) Does Oracle support, if we make changes to above PL/SQL package? Is above package, patch proof?

    2) We also have requirement to add additional information for check printing, do we need to use above PL/SQL package or separate package? If separate package what is the name of it?

Thanks