WS-Addressing behaviour in Mocks

Hi,

I am having some issues with WS-Addressing, my scenario is as follows:

1. I have a TestSuite with one TestCase and 2 TestSteps.
2. TestStep1 sends a request (Q1) specifying a Math.Random() number as the messageId
3. TestStep2 is a Mock which receives the response (R1) with the same messageId in the WS-Addressing header

so far so good...

The problem comes when I try to load test with multiple threads. The Mock doesn't appear to care about the WS-Addressing header, it simply processes all the R1s as they come in, without tying them back to the 'instance' of the TestCase that sent the matching Q1. Thus the 'conversation' doesn't work.

Is there a good way to tackle this?

Thanks,

Chris