It was actually Lakeside's post, but here's the copy and paste from that conversation.
_____
I have the bracket you are talking about, but I have a different method that I think is much easier. I also have a 4-prong connector on my truck, but the trailer has a 5-prong connector...
When I need to back up, all I do is turn my headlights on, which sends power to the second prong on the harness. I unplug the harness, then plug the 5th connector on the trailer into the second connector (first female connector) of the truck harness.
Maybe this makes more sense (forgive the crappy diagram):
Truck looks like this:
O I I I
1 2 3 4
Trailer looks like this:
O I I I I
1 2 3 4 5
Hook the truck's "2" into the trailer's "5". As long as your headlights are on, it will trigger the trailer brakes to release, and you're golden to back up.
That's what I do, anyway... it only takes a few seconds each time, then you don't have to worry about carrying (and losing) the little metal bracket.