I tried something similar using a stream profile and iRule to add a persistence record based on the server response content. You could try using a similar approach for the request content.
Persist Client On Response Content With Stream
http://devcentral.f5.com/Wiki/default.aspx/iRules/Persist_client_on_response_content_with_stream.html
Note that the iRule parser doesn't allow use of the persist command in the STREAM_MATCHED event, but hiding it using eval seemed to work. If you test this further, could you reply here and/or update the Codeshare example with your iRule?
Thanks,
Aaron