I tried to exchange my Fn key with left Control, which didn't work.
I used the command xev to get the keycodes/keysym.
Afterwards I used:
xmodmap -e 'keycode 151=Control_L'
xmodmap -e 'keycode 37=XF86WakeUp'
But it didn't change anything.
I also couldn't create the .Xmodmap to change the keys there.
Did I forget anything? It didn't throw out an error.