The only wiring difference between a trailer with surge brakes that uses a 5 wire harness and one without that uses a 4 wire harness is the 5th pin for the 12V on the reverse pin, usually taken off the backup light circuit. The 7 pin round can be wired simply using the required pins.
No brake controller is used and I can't imagine why anyone who knows ANYTHING about trailer wiring would say it would be. But then, this is the internet where everything posted is correct.
U Haul just wanted to make some extra bucks. You can just pull a taillight find the wire to the reverse light and use a good inline connector. I did this to run some LEDs pods in my bumper. You might look at installing some LEDs back up bulbs at the same time. Much better light output and lower amp draw. I have 48 watt pods, LED back up bulbs, 72 watt flood/spot combos on my trailer and some lower watt submersibles on the sides of the trailer. I like to be able to see when in reverse. Never had any problems with the circuit but I am not sure if the trailer revere wire is on a separate circuit. The pic is the backup lights that I was running before I went to the pods.