Logitech MX Revolution "back" button not working...?

I have been using Dopus since V8 and love it. The issue I am having is that my back mouse button does not seem to work in either ver 8 or 9. It always used to work quite happily in 8 and of course works fine in Windows, IE, Games Etc... I have the latest version of Logitech Mouseware running & have tried remapping the back key just to be safe... Still no joy...

Am I an idiot that is missing something really obvious or what...???

Help me please.

There's a FAQ that explains how to solve this issue.

(It's due to Logitech's stupid default mouse configuration. Easy to fix via the SetPoint control panel.)

Also check how to reactivate middle mouse button - you may want to use it in DO!

I hate this big piece of software (hey, Setpoint is a mouse and keyboard driver, not a game!), but the hardware is great (esp. the revolution).