I would have thought that showing my build.xml would answer the question about how my EAR is structured. And I was never aware that I needed to include a file called ejb.jar anywhere.
Perhaps the question I should really be asking is: where can I find a good tutorial about these topics? I have been jumping from one 'Getting Started with EJB' site to another, and clearly the information I'm getting is incomplete. Compounding the problem is that there are still a lot of old EJB 2.x sites out there, providing what was accurate, but now outdated information.