outputting audio to Airport Express?

I’m new to aTV Flash and the apple tv.
I’ve got a modified AppleTV that has a large hard drive in it that I use as my primary music server.
that being said, I love the aTV Flash functionality but I can’t figure out a way to output the sound to my various airport express units. I can output itunes but nothing else coming from Boxee (like Pandora).
Anyone have a solution? I was thinking something like airfoil for the Apple TV would be perfect. Anyone?
Also, anyone figure out a way to utilize the apple remote for the iphone with the additional functionality of aTV flash?


Unfortunately the only audio that can be streamed from the AppleTV to an Airport Express is the iTunes music that has been synced to the AppleTV.