I hook my MBA to my TV when not traveling and use a desktop with keyboard and magic trackpad. I hook it up via mini display to VGA adapter. The picture is just fine but how do I get sound through the TV from MBA? I've tried using a cord that plugs into headphone jack and on the other end if red/white audio cable but no joy.

Am I SOL and should go buy a HDMI cord? Or is there a way to get this working?