Where have my External Libraries gone!?

As far as I can tell I've jumped through all the hoops for creating and adding External Jars as a J2EE Server Component to my DC project. The Jars appear in in the project properties. I have deployed and tested the project locally and it's fine. However, when I build the DC project, the jars are not added to the WAR hence I get class not found errors.

I sure there's probably one little checkbox I'm missing - I just wish I could find it. Can anyone help?