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?

THanks!
-Ripple

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.