Actually, I'm now using Yahoo Music Engine Unlimited. (which also includes Launchcast) I can use the Yahoo tracks without problem in Xlobby. Basically I download the album I want, use Tag & Rename to format to my liking, move the tracks to where the rest of my music is, and Xlobby picks it up.
Great way to build a large music library! BUT having the ability to tune into my stations would be great as well, perhaps it's possible since there is a plugin architecture to YME?
http://plugins.yme.music.yahoo.com/