Multi button mouse unusable on Mac OS X

Since 1.6.0/1.6.1 Minecraft started to recognize all buttons on my mouse as button 3 (except for button 1 & 2).

I've set the mouse wheel button to be the pick up block button, but when I press one of the unbound buttons (the thumb button is set to PushToTalk in TS3) it though does a pick up block ingame.

When I go into the controls setup, click on one of the actions and then click on one of the mouse buttons it always sets "Button 3" (except for button 1 & 2).