I realize that this won't be possible. Since the freewheel product is using an iframe to display the contents, and the document within the ifram is looking for a querystring reference, there's no way to actually alter the behavior.
Oh well.
Edit: The closest option would be to store the files within a database (or other securable media), write the file to disk upon request, make that publicly viewable and feed that url to the tool, and discard the file after completing the request. That's messy though.
Edited by: jdstroud on Jan 13, 2010 1:20 PM