Create contact person during Inbound IDOC processing

Hi Friends

I am trying to create Contact person using VAP1 transaction(via BDC - using custom function module) during Inbound idoc processing.

This process will create sales order. When I tried to call this BDC function module from z-program its working fine and creating contacts.

But when I tried to create contacts at the time of inbound processing its failed to create contacts using the same code.

I am not sure...This process is possible or not during IDOC process.please let me know asap.

Thanks

Gowrishankar