.fla modification

I need a small modification to the .fla that produces the GUI for the following panoramic virtual tour: **[**[login to view URL]**][1] ** (This is a "launching page". Click the square thumbnail, it loads a fullscreen Flash panoramic viewer with a Flash GUI.) The thumbnail needs to be changed to a different image, (call it a "launch button") but only when viewed on the "launching page". When the user exits the tour, the "launch button" needs to re-appear. The "launch button" needs to be changed by us, so it should be referenced by and xml file or some other method. I will supply you with the .fla and .as files for this virtual tours. I do not want the entire thing re-written, I just need the simple modification.