No Sound with HDMI splitter

I have a new Mac Mini and am new to macs (last one I used didn't have spell checker:)

I want to be able to diplay from my desk LCD TV or a LCD TV (Same Make TVs) that a class room near by can see. I bought a splitter and the picture is perfect, but the sound only comes from the Mac Mini. It works with the TV speakers with just the HDMI cable, but as soon as I plug in the splitter no dice. I went to the Audio MIDI Setup after reading about it in another post and when I have the regular HDMI cable plugged in the HDMI cable shows up in the list of devices there (and works as I mentioned) when I plug in the splitter nothing it never shows up so I can't play with configurations or anything.

Ideas on why this isn't working? Do I need a special splitter? I bought this one off of amazon.