Unfortunately you can't setup FN combinations to the Tactx Keys. That's why the system has the On Screen Display driver that works with the FN. Make sure you have the OSD driver installed.
You can define the primary behavior of the function keys (F1–F12) by changing Function Key Behavior in BIOS setup program.
|Disconnect Alienware Graphics Amplifier|
|Toggle integrated/discrete graphics|
|Switch to external display|
|Disable/enable touch pad|
Dell | Alienware Technical Support
Opening your case does not void your warranty! Check out Alienware Artificial Intelligence
I can't always reply to PM's, if you need extra assistance visit: