Add new fields to MM Condition table (Field catalog)

Hi everyone,

I'm creating a new condition table but it's missing a key field for my pricing on the PO. It's missing field RETPO which tags the line as a returns item.

I know there is SSCUI 103118 to Change Field Catalog but that is only for Sales Pricing, it doesn't apply for Purchasing.

Is there a way to add new fields in the field catalog for purchase orders (MM Purchasing) ?

Thanks!