I have a problem about Sort field in sap script.
Please read below and give me any advice.
I created a custom FORM which is used by F.27 (customer statement).
It's a copy of F140_CUS_STAT_01
I chose P1(Document date, reference/doc.no.) as line item sorting in print program (RFKORD10).
I have a request that sorting in billing document number.(BSID-KIDNO or VBELN)
So, I tried to make sort variant in Tr-CD :O7S6.
But there are not field of billing document number.
How can I sort line items by billing document number?
(If possible, I want to realize it by making sort variant only.)