they won't host animation files on their server AFAIK. that's what they've told me a coupla times. there at least two possible reasons:

• no standardised animation file format (meaning one never knows what filetype it is until one downloads it)
• large file size (meaning they will slow down an already glacial server farm)

so the best bet is to upload one's video to youtube. the advantage there is that all the files are served as streaming flash video (or so I was told), hence at least one always knows what the filetype is, how to play it, and which browser to use.