BAPI_PO_CREATE1 with generic material

Hi experts.

I'm trying to create a program to automatically create purchase orders using BAPI_PO_CREATE1. The problem is that the orders can contain generic material, in witch case the quantity of each variant must also be passed to the bapi. I currently haven't figure out where or how to pass these values to the BAPI...

Is there any way to create the orders, other than BDC?

Thanx in advance