standard partner schema in SRM PO
Im confused with the partner schema used by standard in SRM PO.
There's no assigned partner schema in PO transaction type but when I create PO, I can add partner functions - vendor, goods recipient, location, address, etc, both in header and item level.
Where does SRM pull out this list of partner functions when there's no assigned partner schema in the transaction type?
Reason asking is I need to add Invoicing Party in the existing, and according to note
I just need to add the invoicing party in SRM PO and maintain the vendor master partner function in ECC , and it will be determined automatically when the PO is replicated. So I'm thinking if I need to add the existing partner functions in the new partner schema I will assign to the PO transaction type, so I'd need that list of partner functions used by standard.
Any help is appreciated.