Eforcity has the RCA Audio Cable Adapter for Microsoft Xbox 360 for $11 - $2 off with coupon code EFWS031523 [Exp 3/21] = $9 with free shipping. Allows HDMI video to be routed to the HDTV with the audio routed separately to the home theater system.
you will have to open it up and solder 2 points together to make it work properly. If you dont, then the xbox will reset if you decide to change inputs on your TV (ex. you are playing a game, you hit pause, you switch the input to check something on channel 7 news, you switch back to your xbox, it will reset)
its cheaper on eBay, from the same company
http://cgi.ebay.com/Optical-Audio-Adapter-For-bacon-HDMI-AV-Cable-Gaming_W0QQitemZ300407646963QQcmdZbaconQQptZVideo_Games_Accessories?hash=item45f1b0eaf3
you will have to open it up and solder 2 points together to make it work properly. If you dont, then the xbox will reset if you decide to change inputs on your TV (ex. you are playing a game, you hit pause, you switch the input to check something on channel 7 news, you switch back to your xbox, it will reset)
here is the guide to fix it: http://forums.xbox-scene.com/index.php?showtopic=691179
the fix only takes 5 min.
Nice! Thanks for the tip, I had been using component because of this nonsense.