My question is re: how to resume the flow after a queued step. In a simple case, user goto web to create a PO request, since the transaction also need to sent to a legacy system for processing which is queued thru MSMQ. after this is done, then we need to resume back to next step ,say for shipping or mail a invoice to user.
How to implement this using WWF.
Appreciate any inspiriting thought.

Long run business process
eriks70012
Paul , thank for the reply. I can see there are two issues in your suggestion:
1. In order to receive the return msg and move to next step, the host has to be alive for a long time which is risky , especially when we host the process in IIS , like using webservice.
2. Correlation , I think I can get it done in BizTalk, but I don't think MSMQ has this concept, maybe SQL 2005 queue service.
Correct me if I'm wrong.
Matt Spy
In WF the key piece you would need to implement is to write a couple of activties that send and receive MSMQ messages. The receive activity would block the workflow until the correlated MSMQ message is received. As part of the receive activity you write there would be code in the host process to receive the MSMQ message.
Regards,
Paul