Microsoft Wireless Mobile Mouse 4000 button problems

Hello,

I had been using a Microsoft Mobile Mouse 4000 (black) with my Mac Pro 2009 running OSX Mavericks. The mouse was at least four years old. The mouse's scroll wheel has stopped working, so I replaced the mouse with a white version of the same model.

However, when I began using the new mouse, it's "button 3" on the left side, which is supposed to be used to go back in web browsers, functioned as the wheel button (middle-click). The wheel button also used the middle-click designation (which is fine.

I've tried the following with no resolution:

1. Attempt to change mouse features in System Preferences/Microsoft Mouse (with Intellipoint 8.2 for Mac). Though labels indeed changed, functions remained unaltered.
2. Uninstall/reinstall Intellipoint 8.2 for Mac. Functions remained unaltered.
3. Reset PRAM (thought I'd try it). Functions remained unaltered.

Frustrated, I switched back to the old mouse (just plugged it in, no changes to software). It functions as it had previously- all buttons work as they ought, but scroll does not work.

Any help getting this newer mouse of the same model number to work on my Mac would be greatly appreciated.