Using correlation and Send / Receive

Summary

Link to good demonstration required

Content

Hi,

I am creating Process A that calls process B.

I want process A to call process B, then wait for process B to call process A back before process A continues.

 

I have implemented this using Send/Receive tasks and correlation ID.

I am having mixed results with the correlation, sometimes it works, sometimes it does not.

Can anyone provide a link to a good worked example of how to set up correlation to ensure that when process B calls back process A, I can ensure process B routes back to the correct instance of Process A.