Trailer Plug Magnet

[Brute6]

Just want to put this out to the general audience - the trailer plug connector that sits under the rear bumper on Falcon/Territory, has a very small magnet in it, just above the row of pins. For those that don't know, that magnet is there for when the vehicle has reverse sensors attached, and when the trailer plug is used, the magnet then sends a signal that stops the reverse sensors "beeping" when the car is in reverse (hopefully that makes sense!)
What I need to now, is do I have to purchase a whole new plug (vehicle end) or can I simply get another little magnet thingy to replace the one that has fallen out?
Hope someone knows what I'm talking about!!