Substitute Document Header Text in Callup Point : 9 (Line Item)

Dear all

I want to substitute document header text based on trading partner(BSEG-VPTNR).
I opened GB01 and set substitution in callup point 9, but it doesn't work.
Is it impossible to substitute header text in point 9 (line item)?
or do I need to make append structure or something, too?

Best Regards,

Chihiro