Sein
find all key mapping in terminal using
xmodmap (for spcial keys)
xmodmap -pke (for all the keys)
Its easy to set for unused keys like F11 or F12
i tried for F12
xmodmap -pke | grep 'F12'
find the keycode (eg. for me its 96)
xmodmap -e "keycode 96 = a A"
if this works then make an alias or create a persistant keymap file and .xinitrc file in /
xmodmap -e "keycode 96 = a A"
xmodmap -pke > ~/.xmodmapkeys
touch ~/.xinitrc
echo '#! /bin/sh' >> ~/.xinitrc
echo 'xmodmap ~/.xmodmapkeys' >> ~/.xinitrc
reboot and test.