Unfortunately using overflow: scroll; doesn't acieve the desired effect. It looks awkward with the horizontal scrollbar (which is not needed) and also requires me to set a fixed height on the container, which makes it look odd if you maximize the help window (it's resizable). Also, I need to be able to "jump" to specific anchors on the page when it opens, depending upon what help item the user clicked, and simply adding scrollbars to the container doesn't prevent the entire page from scrolling down and hiding the header.
Guess I'll start experimenting with frames...
Cheers!
-Sean