If the Mac can do it (which I now kind of remember),you will need to export your animation as a series of png (or tiff) files which support transparency rather than a *.mov file and use the images in your flash app.
Still I'm not sure it could be done with an animation even on the Mac but good luck!
It isnt available native in SU, but there is a plugin called 'nudge'that will let you do this. See the link below.
http://www.smustard.com/script/Nudge
There are, in fact, "snapping" settings in SU (Model Info/Units) but they apply to length (of line) and angle increments. These can be turned off, but inferencing cannot. Which is just as well since SU would be unusable without it -- you would be lost in space.
