This may also help:
http://www.thinkwiki.org/wiki/Installing_Ubuntu_11.04_(Natty_Narwhal)_on_a_ThinkPad_X220#Fix_for_hotkey_shortcomings
This may also help:
http:// www.thinkwiki. org/wiki/ Installing_ Ubuntu_ 11.04_( Natty_Narwhal) _on_a_ThinkPad_ X220#Fix_ for_hotkey_ shortcomings