Batch determination and ATP

Hi Gurus,

I believe that there is no BAPI or FM that is released by SAP (If there is please let me know) that will do the batch determination. So what I did is I created a BDC for batch determination of VA02. The batch determination is working fine for items that have sufficient batch stocks. But I have a scenario wherein if the batch determined has a qty that is less than the ORDER QTY, the availability check screen appears.

How will I handle in my batch input this scenario. I cant use the BAPI_MATERIAL_AVAILABILITY to check the stock for the batch because I dont have yet the Batch Number before i check the stocks.

Thanks,

Andre