Movement controls

Mouse navigation on the Mac: I have an elderly Apple mouse with only one button, but on MOULa I can walk backwards using alt+mouse down (= middle button on the navigation settings), and stand still and look around by using command+mouse down (= right button). Doesn't work on Gehn: neither alt nor command have any effect, I just walk forwards all the time. Any ideas why? Is this a Wineskin thing, or is it a current limitation of the client? Or am I missing something obvious?