EDI PO Acknowledgements(855)- A Query

Hi Experts,

We have the following business process.

I want to know the best possible technical solution.

Customer send a PO (850 Signal).

We map it to ORDERS.ORDRES05 IDOC and it creates a Sales Order in the SAP ERP System.

This scenario is working fine.

Now the customer wants a PO Acknowledgement signal (EDI 855) in response to his 850 signal.

We are planning to trigger an Order Response Idoc ORDRSP.ORDERS05 whenever an order gets created.

and map that IDOC to 855 signal.

But the problem is , how do we send a negative 855 signal in case the 850 doesn't create an Order in the backend succesfully?

I want to know how do we acknowledge the Po in both case.

i.e. When the PO succesfully creates the Sales Order in our system and when it doesn't.

Please let me know your valuable comments and suggestions.

Regards,

Ravi kanth Talagana