How to get sound on TV to come out of stereo?

I have a Magnavox HDTV with 1 HDMI input, and I'm soon getting an xbox 360 with An HDMI output, but when I plug my HDMI cable into my TV I want the sound to come out of my stereo reciever. On my old TV all I had to do was plug audio cable from the tv to the reciever so that whatever sound comes out of the TV will come out of the stereo...thats what I want to do, but the TV I have now dosn't have that kind of output. The only output I see is SPDF..whatever that is...PLEASE HELP!