Make sure Windows media recognizes it as an audio device (right click on the speaker icon in the tool tray and open the dialog box; click on the "audio" tab and make sure the Fast Track is selected (should already be, since the other software recognizes it -- just trying to be complete).
In AA, go to Options/Settings/Wave In [and Wave Out] to make sure the inputs and outputs for recording [playback] through the Fast Track are selected.
Then Options/Device Order and tick the box that says "use in EV" for the first pair of Ins and Outs -- otherwise you won't have any sound playing back in Edit View and you'll go insane trying to figure out why.
If this doesn't work, let us know.