I need help; i don't know how to do it, but i know it's possible.(has to)

My relatives asked me if i can stream a foreign video url ( with audio) from
their mac to their apple 2 tv.

Things i have:

I have the Beamer app (v.1.2) - Which can airplay (almost) any video file. Does not play url's. ;(
I have VLC
I have Apple TV 2 ( not jailbroken - not allowed to)
I have Perian
I have (most) video converters - Handbrake, VisualHub...etc
I have a newb-ish brain. (especially when it comes to formats+servers and stuff)

Things i did:

I tried to do transcoding with vlc...only to find out that Beamer ( or any video player for that matter)
opens it only until the whole video stream is downloaded... i need it live

The gist of it:
If Beamer could have been able to open video url's - i would not be posting this question.
Since it can't, i need a way to convert a url stream into a "video file" that Beamer would open.

If anybody can help me on this, it would be greatly appreciated...

*big pleading smile*