Modifier buttons on mouse don't work with Macbook keyboard presses

So I play WoW on both my laptop and my desktop. I just bought a Razer Naga and it works great with my desktop. I have buttons bound to control, shift, and alt.

My Macbook Pro, however, is different. Using my Naga's modifier buttons still works with clicking, so I know the buttons work. But using the mouse modifier buttons with keyboard key presses doesn't work. The key presses aren't modified when I use the mouse buttons.

Any way to fix this?