how to rebind move between windows

[Brendan Miller <catphive catphive net>]

I want to rebind the move-between-windows-immediately key. I'd like 
super-u and super-o to move to previous and next windows.

In the Keyboard Shortcuts control panel, there is only one entry for 
"move between windows immediately." When I set it to super-o (mod4+o) 
the new keybinding does not work.

Does anyone know how to make this work? Also, is there some hidden 
setting so I can have separate keys for moving to the next and previous 
windows?

I'm using gnome 2.32.1.