Cannot rewind DVR-MS files with F5. If you do then you will be set back to the beginning immediately. Does not matter if you play from MyVideos/TV Recorded shows or in timeshifted TV. It doesn't seem to depend on the codecs that are used. I tried Cyberlink and Intervideo and both show the same issue.

BTW; Forwarding with F6 works fine.

Reported in the forums:
http://nolanparty.com/mediaportal.sourceforge.net/phpBB2/viewtopic.php?t=4532&start=0&postdays=0&postorder=asc&highlight=