Instead of having that one installed, have your dealer give you the factory one. You get a new factory keyfob like you current one but it has the remote start button on it. Then the dealer connects their IDS computer to your truck and enables remote start in the trucks computer. Most dealers don't know that it's possible to do this on '11-'13 Explorer and '13 Flex's. Basically here is the procedure, no add on devices necessary or wires to cut. Best part about this way is all the remote start menus are accessible in the gauge cluster such as climate functions and duration.
-Get key from dealer and have it cut.
-Program new key to vehicle (must have 2 already programmed keys to do this yourself or dealer can also do it) Takes about 1 min to do.
-Have dealer turn on remote start with IDS tool. About a 15 min job.
Make sure to get the correct key for you truck. Either with power liftgate (5 button), or without it (4 button).
Here is the thread on the correct part numbers depending on which keyfob you need, pages 3-4.
http://www.explorerforum.com/forums/showthread.php?t=333902