ok, now i understand what you're after. i don't think it's possible to play back a track and record a separate one at the same time.
I'm pretty sure it should be possible - it'd be a strange multitrack recorder if it didn't...
Until it was set in the control panel I had the same problem. Once you do it you can record into via UA-5 and have playback on your soundcard.
Have you tried this yet?
I'm not sure what I'm meant to be trying here - the only options I get through the Control Panel are enabling/disabling recording and/or playback for individual devices. I adjusted these (so that playback only is enabled for my internal soundcard while only recording is enabled for the UA-5) after your first reply. I thought by doing this I'd be 'forcing' the output through the internal sound device but still get no output.
I think this may be because Audition only 'sees' playback/input devices from within the currently selected driver. So if I choose the UA-5, my only outputs are via the UA-5...
I'm baffled as to how you are able to configure Audition like this while I can't - can I check that we're using comparable setups? I'm using a Busman modded UA-5, laptop PC and Audtion v3.