FPCJ Issue

Hello Experts,

At level of cash journal t-code FPCJ, when the action "post" is chosen our customer needs to :

1- Change default value for field BLART of the payment document created (document P1)

2- Create a specific document (P2) to include a specific tax, this document must be reconciled by the same payment document P1 (so we have to change the amount of the document P1 to include the tax amount),

I use the BAPI  BAPI_CTRACDOCUMENT_CREATE the create the Tax document, but I don't know at wich level I can change BLART and amount for document P1 and finally reconcile P2 by P1

Have you any idea of event (FQEVENTS) or any place to do that ?

Thanks