[Help - Audio] Mac and HDMI

[International 4-8818]

So I bought a mini adapter to HDMI cable for my mac so that I could connect it to my 1080p screen. The problem is, it being HDMI, it should broadcast the sound from my comp. to my television, right? So far it is still playing it off of my comp. speakers. Is there anyway that I can make it play off of my television speakers?

[Aizmov]

Did you try going to System Prefrences > Sound and change the output device?

If that doesn't work you'll need something like this:
http://www.amazon.com/Kanex-iAdapt-DisplayPort-Channel-Digital/dp/B0031QH1BG/ref=sr_1_6?ie=UTF8&s=electronics&qid=1280228765&sr=8-6

I could be mistaken but not all Macs can output sound via Mini Displayport.