Is it possible to make the background invisible in an flash desktop application?

Hey there,

I am currently trying to build a small desktop application in flash which works a bit like the scmpoo sheep (scmpoo - Cute little lamb / sheep on your desktop - YouTube). A screenmate with just a few animations and a movieclip tied together in as3.

My problem now is, that the animated animal should a least look like it really moves on the users desktop, since I found no way to really place it there.

I already set it to fullscreen mode, which removes the borders but I can't find a way to make the backgound invisible/transparent. In web-browsers this seems to be quite easy, but does it work for the desktop flash at all?

And if yes, how do I do it?

thanks for helping