So I started this sample out as an off-the-cuff kind of thing and it seems a number of people are using it. Lenny Fenster from Microsoft found another bug - when the child workflow would terminate with an exception - the CallWorkflowService was sending the exception to the Queue - but the custom Activity listening for the message wasn't re-throwing the exception. Its been fixed - so if you are using this sample - you should download the new code. Orginal Post . My samples page. Check out my BizTalk R2 Training . Read More...