I use a photo hosting site (photobucket) and upload my videos there and then post the link here... I'm not sure if there's a way to do it as you're describing. Maybe someone else has had success that way??
you cannot download the movie directly onto here, you need to use another site in the middle like photobucket or youtube. Go an make a free account with one of them (I prefer youtube for movies, it's easier and the movies flow better to watch them!!!) and you can upload your video onto there, and then just post the link over here for us to see.