help with video playback

[AppleNewton]

I have VLC Player installed on my mac and i want all my videos to play through that, there are some videos on the web wiht .wmv and .mpg extensions that dont automatically launch in VLC player (however there are some .MPG's and .WMV's that do... .AVI's open in it aswell.)

because some videos download and then auto play in VLC while some play in the browser.

Im using:
Quicktime 7 Pro
VLC
Firefox 3
all the latest updates.

here my firefox settings:

thanks!