Here is the braking requirements as laid out in a pdf brochure published by ODOT:
http://www.google.com/url?sa=t&rct=j...63738703,d.cWc
Towing a Trailer in Oregon, Being Equipped for safety.
"
Brakes: Any combination of vehicles must be
equipped with brakes that are adequate to stop
within a certain distance. While traveling at a speed
of 20 miles per hour without leaving a 12-foot
wide lane the combination of vehicles must be
able to stop:
Within 25 feet for those vehicle combinations
under 8,000 pounds.
Within 35 feet for those vehicle combinations
over 8,000 pounds.
Oregon law does not require trailer brakes, but
their use is strongly encouraged as an additional
safety measure. Oregon law requires that all safety
equipment that came from the manufacturer on
your vehicle, including brakes, be kept in good
working order.
So if your trailer is equipped with
brakes, they must be kept in good working order.
You must follow both the tow vehicle and trailer
manufacturer's recommendations for all aspects of
towing, including the use of trailer brakes."
The way I see it, the Trailmanor has electric brakes installed, therefore you must use them.