From FSD document in TM to Create PO in ERP with other than item category U

Hi Gurus

I want to create a PO for the FSD document from TM .

While doing so it is automatically taking the Account assignment category as U.

Because of that the Service entry sheet is not updating automatically.

Can you please help me to create the PO in MM for the FSD with account assignment category as K or other than U.

Thanks in advance

Mahi