Creative was no help, but I found a third party program that recognizes the extra mouse buttons (X1 and X2) under Vista 64 and can remap them to any key on the keyboard. You can set up multiple profiles (Ie. for different games and such). For example, Lost planet does not recognize the buttons so created a "lost planet" profile and remapped the buttons to F11 and F12, and then set up lost planet to use those keys.
The same strategy would work for other applications. The re-mapper is supposed to work under XP 64 also. The download is free, and the features described above work with the free version.
http://www.atnsoft.com
Key Remapper
Hope this helps.
