Full browser movie, but use browser scrollbar when needed

Is there any way to make a full browser swf that, at a certain point, stops scaling to the stage and allows the browser to use it’s native scrollbars?

For example, say my flash site has a top bar (it’s y is always 0) and a bottom bar (it’s y might be stageHeight - 15). Is there any way to tell the movie to stop scaling if the bottom bar’s y is less than say 300, and from that point have the browser display it’s scrollbars allowing you to scroll the content?