Hello Scott

If you go into the Business service that is doing the immediate ACK back you will see under Development and Debugging a check box for Archive IO. Enable this and it should then show you the ACK in the trace once you send another message through. 

When you are done with looking at the ACK I would turn this back off as it adds to the space being used by the trace messages. 

I hope this helps

Alex has suggested the best way. You can also suspend these messages so that they can be looked at and resent later. You can send an alert also from any point if you wish while processing the messages. 

http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=...

Lastly if you get a lot of these that need to be touched or messages in someway by a real user you could use a workflow in your production. 

http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=...