BPM error handling for async/sync

Hi,

I am using an async/sync bpm for sending a message from SAP using outbound proxy to call a synchronous web service.

Now, if I get a fault message from web service the queue will be blocked for other messages to flow through as it is an EOIO.

Can anybody suggest how can I get the fault message and errors out in PI with a red flag and not block the other messages to flow through in this design? I cannot change this design as it is the business IT suggestion to go through in ths way.

-Mike