Hi,
If I understand you correctly you have JMS client that you want to test against mock service.
You can do this with SoapUI 3.5 .
SoapUI can send-receive against queues and publish-durable subscribe against topics. So you can for example receive message than do something with it and send back to same or another queue or topic. For this you need to create sequence of operations (Test Steps) and loop that sequence .
Can you explain more your use case, so we can help you find a solution for your problem.
Best Regards
Nebojsa
eviware.com