Air Play for ATV 2


I have realized, that using AirPlay from iTunes to the ATV 2 allows you to control (at least pause etc) the itunes. Since I have also an Airport express, which is only used for streaming music, I was wondering if the ATV2 could also stream music via Airpaly to another reciever and control the speaker on the itunes computer itself. Since IOS in general can do it from an Iphone/Ipad etc and there is a simple hack to enable an iOS device to be an Airplay reciever, it might also work  the other way arround.

The media player on the ATV2 It would be like the remote app on the iphone/iPad etc.

Any ideas on that?