What happens when you set Line-In as the default? Is Audition still unable to use it then?
I just set Line-In as default and now the little meter moves but the levels slider still does absolutely nothing and Audition still doesn't seem to know Line-In exists.
The only way to set the levels is the move the volume on the device that's playing the sounds (the MP3 player in my case) but that's not a big deal.
The Vista Sound Recorder picks up Line-In now but that tiny little meter is pretty useless for figuring out if your levels are set correctly. What you hear out of the speakers is just a signal going straight through your soundcard and out of the speakers. It's
not the actual sound that's being recorded. Your recording could be too loud or too quiet but you'll never know until you listen to the file you just made.