Apple Aluminum Keyboards
This is a known problem with the new Apple USB keyboards (aluminum body) and older Intel Macs (e.g. Early 2006 and Mid 2006 models). The keyboard works in Mac OS X, but does not work in the rEFIt menu. It also does not work in the built-in boot menu, since there is a general incompatibility between these newer Apple keyboards and the EFI firmware in the affected Mac models.
There is nothing rEFIt can do about this, since it is a driver problem in Apple’s firmware. If you want this to work, ask Apple to fix the firmware.
The older Apple keyboards (the “white” ones) are known to work.