Stretchable swf in Firefox?

Newbie, but I have a good question if someone would like to give it a go.

In Flash’s publish settings, under HTML, you can set the exported swf to be stretchable (dimentions: percent). This works fine in IE, if your height and width are set to 100% within the object tag. However this is not the case with Firefox. Even if you set the embed tag to 100% width and height, it will extend the background and show any off stage elements, but it won’t enlarge or shrink proportionally to your swf movie. (See attached for visual.)

Solutions?
A friend of mine has one, but its a nasty JS (uboodu.com)
There must be an easier way.
Cheers