Use KeyRemap4MacBook (Karabiner for osx 10.9, 10.10). As Mecki pointed out, XML .keylayouts / Ukelele can’t solve your problem.
In spite of the name, KeyRemap4MacBook works on any Mac (OS X 10.4 or later).
The settings you want are under “For PC Users” ยป “Change PC Application Key”.
