PaspPi & Keyboard Mapping

A simple question – using RISC OS Alphas on a Raspberry Pi. I have an Apple Keyboard (of the kind supplied with the original iMacs and PowerMacs), and in RISC OS, I have it set to use an American keyboard, so the " and @ keys are in the right place.

However, I have been looking at an application which requires an ALT+Mouse Click. It seems that the ALT key on my keyboard is being ignored. Is there a way to set up key mappings, so I can make the press of the ALT key mean that to the OS? More importantly given that everyone will be using whatever keyboard they have got their hands on, it would be helpful to be able to have somewhere where these settings can be made available to anyone who needs them.

Would either MouseKey or Keymapper be of any help?