As Kaibach says, the pre-defined button 1 should switch between camera mode and direct manipulation (does the same on a Space Navigator and Space Pilot Pro, it's a default driver thing rather than hardware specific).

As for the other buttons, you should be able to edit the poser profile in use in the 3DxWare control panel button configuration tab. Pre-def button 2 switches to the memorised camera view I think, the others don't seem to be setup to do anything, but you can just create custom functions of your own and assign them to the buttons you want.