Header Text using bapi_po_create1

hi,

I created a purchase order with header text using bapi_po_create1.But now my requirement is to populate all the header level texts through flat file with po data at a time .The problem is in bapi_po_create1 there is only one parameter in tables i.e.poheadertext ,so how can i pass multiple internal table ,as i am not able to create one internal table including all header level texts and passes to the same parameter but it's not working...

KindlyReply with sample code....