I am trying to make a site with elements that resize dynamically depending on the browser width, but have the foreground element stay the same size all the time?

The first part is easy to do. If I set the height and width of the Flash file in the HTML to 100%, when the browser is resized, the Flash will also resize.

But I can't figure out the second part.

An example of what I'm trying to do is at Rilo Kiley's website

Another example is gskinner.com

No matter what your browser size, the background scales and the foreground is always the same width and height.

I am using Flash MX 2004.