Media RSS/Mp4 Format broken

I have tried to use the media RSS with Channel9 videos in my new phone (Nokia XpressMusic 5800).

Well, there is no way to see the videos offered and I think there is a problem here:

• Nokia, supports Media RSS format in order to get videos from Media RSS feeds. Nokia Video center selects type="video/mp4" videos from the feed in order to download and playback. So far so good, as Media RSS Channel9 offers links for this type of videos.
• Channel9 offers .mp4 videos that are "labeled" as type="video/mp4" but they are actually type="video/x-hx-avc1". Media RSS feed offers two links for type="video/mp4" videos, that are actually the same video file. What is the problem with this?
• Most of the mobile devices do not have the process power to decode this type of videos as hardware support is required in order to achieve that. I would like to ask, that type="video/mp4" videos would be actually .mp4 videos (the original .mp4 format).
• It would be nice to keep type="video/x-hx-avc1" videos as they are encoded in a better format, but marked with a different type, in order to be easy to be recognized my Media RSS players.

Regards,
George J.