Dynamic reflections - how to create?

Hi - any ideas re how to creat dynamic reflections, eg as if a light were shining across a surface (glass/chrome) in flash?

not sure how to mask it .. appreciate any thoughts..

It's probably a lot like this:

http://www.flashkit.com/board/showth...hreadid=451325

Only thing is, a mask can not have a alpha fade in the mask part. Whatever size the mask layer part is, it all shows through at 100%, no fade out at the edges. You can put the fade in, but it just won't work as a fade.