Hi Paolo, most of the time the way .swf files will work is that there is some other service that you upload the video to, and then there is an "embed" code that you can paste into a message here to display the video inline.

For an example of that, see here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2042.25

It also should be possible to upload a .swf file as an attachment here instead of to another service, to do that you will need to enter in the embed HTML code yourself. You'll need to get the address of the attachment file - to do that after you upload it, right click on the link for it and choose "Copy link location" to copy the address to the clipboard, then you can paste it into where it needs to go.

The HTML code you enter for showing an embedded video is like this:

<embed src="your_attachment_address_here" quality="high" width="801" height="601" type="application/x-shockwave-flash" allowfullscreen="true" scale="showall" />

Replace the "your_attachment_address_here" spot with the address of your particular uploaded attachment, and replace the width and height with the actual width and height of your video.

Please let me know if that does not work for you!

- Michael