Just answered my own question:
http://kb.snapstream.com/Kb.aspx?kbid=1128
Combine that with the revelation that you can't stream live TV with a PVR250, and I'm suddenly really dissapointed. I mean, if my system only uses about 25% of the CPU time to encode and decode the MPEG2 (during FSUI live tv), that leaves another 75% of the CPU to encode that same stream to WMV and stream it. And it's not like I'm asking for high resolution video. That 75% should get me 320x200 WMV in realtime.