You want to use them as a background for a layer, or for particles?
The Mac version supports Quicktime only, and the Windows version supports AVI (not Quicktime). You can convert to PNG image sequence which is supported by both versions.
If you’re going to be using them for particles, then you can add them to a library, but that’s not really “permanent”, as they would be available to that one library only.
Alan.
http://www.wondertouch.com