Vista Business Video Preview not working

Hi there,
I'm currently running Vista Business and as I'm working with quite a few
*.avi and *.mpg files for various projects, I was hoping on seeing this nice
video preview I get when opening a folder in Home Premium. Well... the
preview function seems to work, but only for *.wmv files. I already checked
if the "Always show icons, never thumbnails" options was accidetally checked,
but it wasn't. As I'm at work, I can't switch to another version of Vista so
I was wondering if there's some option to switch the video preview on for
Business to help me with my work...