RMB+Shift = Zoom / RMB+Ctrl = Pan not possible?

Hi there, in a lot of software packages it has Shift as the zoom option and Ctrl for pan. This is the way it works for the MMB. At my site the controls are switched for the RMB. I couldnt find a way to set this the other way: RMB+Shift = Zoom / RMB+Ctrl = Pan

How can i do this?

Regards