Apple TV sound won't work through HDMI

We just purchsed a new Sharp 60" LED, with 4 HDMI and optical audio.

The TV optical is connected to the optical on the surround. Everything works great...except for AppleTV.

The Apple TV sound only comes through the TV speakers, it will not come through the surround.

We have to disconnect the tv optical from the surround and plug in the Apple TV.

This is very annoying. Any ideas how to fix this?