Tracks 17 to 34, no sound.

In Logic Express 7, tracks 17 to 34 are GM MIDI instruments, Grand Piano, etc.
I have been so far unable to get them to generate any sounds.
In a regular MIDI track, I can load an instrument, and it plays and records just fine using my Oxygen8 keyboard. But when I select one of the GM MIDI tracks, with a dedicated instrument, nothing. Are the sounds on these intended to be part of the keyboard MIDI software? The Oxygen8 is just a controller, it has no built-in sounds.
I tried setting the controller to a channel 17 or above, but no luck. Are these GM MIDI channels functional?
How do I get them to work?

Thanks,
Bruce McMath