Also check local Locksmiths, they can purchase the software to add keys to PATS systems, if there is no Ford dealer on the island, then I am sure at least one locksmith will have the software since people still lose keys, lol.
If you have 2 working PATS keys you can add a 3rd yourself, so I would get 2 more keys, so you have 3, if you lose 1 you can get another and program it yourself.
The PATS has 3 main parts
1. The computer, it stores the unique ID of each programmed PATS key in memory
2. The receiver/transmitter, in the steering column near the key slot, it is powered and connected to the computer by a wire
3. The PATS RFID key
When you turn the key on the receiver/transmitter sends a short RF burst, this gives enough power to the RFID tag in the key for it to broadcast it's unique ID number(key has no battery inside).
The receiver sends this number to the Computer.
The computer compares this number with the codes it has in memory, if a match is found PCM(engine) system turns on, if no match then no PCM, no start.
receiver/transmitter is not unique, so can be replaced if you think that is the problem.
Keys and computer are unique so need to be matched
So replacing receiver/transmitter, key switch and key wouldn't change anything, computer would still not turn on PCM until it was programmed for new Key IDs