If you have a fairly new F-150, get the replacement handle with the keypad, Mine cost me $56 and half an hour to swap out the handle. Some of the early '05s you had to get it activated, but the later ones are already turned on, just plug and play as they say. Pop the door panel, don't forget to pull the bottom two speaker mount posts, and see if you have the plug in the door. Grey round six pin connector, usually has the dust plug in it.
FYI - While coping some wiring diagrams for my tailgate lock / door ajar mod I came across the procedure for adding keys when you don't have two. You still need the "magic" box, but all they do is erase ALL the keys from the system. Then it will accept the first two keys used AUTOMATICALLY !!!