The ATV can be controlled with an just and iPad. The only two wired connect the ATV need are power and the HDMI connection. The HDMI connection can either be run through your AV reciever or directly to the TV. If you have a strong wireless signal on the ipad&ATV from the Airport it should work without needing the Airport express.
Yes, that was the question.
Alright, that's a pity then. The Apple TV is for sure done to be connected to a AV receiver, at least for the sound. With all the new AV receiver with network capabilities, weird that the Apple TV doesn't provide a bridge.
Damian, I meant to connect the iPad to the AV receiver, not the Apple TV.