Grab the latest git commit,
you'll find a new option under "general option" -> Audio CD.
Check "Use CDDB" if you want to have album,artist and track names auto filled; that way, you can search for covers too.
Note that the first time you will play a new Audio cd with cddb enabled xt7 may hangs, waiting for mplayer to connect to freedb to catch cd informations.
However, this will be cached, so next plays will be just fine.