Credit to FutureC on TheGreenButton for this find
You can convert WTV files in windows 7 (build 7048) to the old DVR-MS files! Just right-click on the WTV file and select: convert to DVR-MS.
If it works, this solves several issues. Among them:
*Playback of Win 7 recordings on Vista (non TV Pack) and MCE 2005 boxes.
*Editing Win 7 recordings with programs that work with DVR-MS and not WTV files. (Commercial skippers, VideoRedo, etc.)