Thumbnail view of exported mpeg files in MCE 2005 no display

[bguidizi]

I have a problems with thumbnail views of mpeg files in Windows Media Center Edition 2005 in the my video portion. AVI files thumbnails display no problem. But digital video I capture then export via v 4.0 of Movie Factory to an mpeg file does not display the thumbnail in MCE 2005. It will display in explorer.
If I export or create an mpeg in Studio v7 it will display in both explorer and MCE 2005. Anyone seen this?