IDOC-XI-File Scenario -Response?

I know how to configure R/3 to send IDOC to XI, and then XI-File configuration. I read how-to doc on acknowledgment, it assumes the receiving party is also on R/3 where they configured AUDIT to send response from receiving party. But this case is receiving party is non-SAP Application.

How to handle acknowledgment to update the status records on sending IDOC in this scenario?