I wanted to do the same thing with my home theater system too. I ultimately just plugged both the hdmi cable and the component cable into the back of the 360. There's plenty of videos on youtube that show you how to do it. Once I did that, I ran the optical cable from my component cable directly into my home theater receiver just like someone mentioned above and then the hdmi to my tv. Everything worked perfectly. You mentioned you have an extra set of component cables so I'm assuming you wouldn't mind taking one apart for this. I did and it saved me $50
