Assignment BSEG-ZUONR in GL Account missing

Hey SAP gurus,

When I post an accounting document through EDI interface, the "sales order" is populated in the Assignment field (BSEG-ZUONR) of the reconciliation GL Account of the Vendor (Credit), but not in the In-Transit account (Debit). I have tried to solve the problem with sort keys, substitutions, implementing note 116023 "BSEG-ZUONR missing in FI document" but I cannot get the "sales order" in the Assignment field (BSEG-ZUONR) of the Debit account (not the reconciliation account). Could you please help me?

Thanks,

Gerardo