The DWF functionalty is something that many people use for sharing info internally or externally in their office workflow. Autodesk Labs website has released an add-on that allows for he firefox browser users to be able o navigate and view DWF files like the Internet Explorer.
Yet another ever changing workflow, that helps the world become flatter!!!!!
http://labs.autodesk.com/utilities/firefox_adr/
Folow the attached link to be able to see it for yourself.