Post Videos in Forum

Is this possible? I am starting a forum and rather than have my potential users directed to the Vshare script I would instead rather like to post the video as a message (like youtube) where users can then comment?

I browsed the "website promotion" area and tried to post link as

[flash=600,400]www.theirdomain.com/theirvideo[/flash]

but all I see is a white box with no video. Youtube videos however work fine.

If I purchase vshare is this just something that needs to be enabled in admin area and will work for me, or is a mod required?

thanks help advance