New Buyers Workbench Center in R12.1.3

Hello,

We are currently using the CUSTOM.pll library for custom validations of various PO Forms. Now with the new Buyer Workbench Center functionality is available in R12.1.3, we still need the ability to add custom data validation functions for the PO documents.  Is there a pl/sql package available to add in custom data validations functions for PO documents similiar to the POR_CUSTOM_PKG pl/sql package used for Requisitions in I-procurement? If so, what is the name of the file?

Thanks in advance

Bettye Branch