I don't have a good picture, but I bought a pair of rear flaps for a small pickup, the straight cut, not the fender flare style. Mounted it to the pipe in the center of the bag guard unit with a 'c' type clamp with a metal inlay to hold it straight down.
The thin black line is the flap. Seems like it measures 8 X 12", but don't hold me to that.

There is a black shadow under the license plate and behind the trailer ball. That is the best picture I can come up with on the bike.

The TAZ, part # 580 is the one I got and trimmed down to fit. Took excess from the top. There is a slight inward cut (Factory) on mine on one side, but you never see it.
http://www.autozone.com/autozone/accessories/Appearance-and-Personalization/Splash-Mud-Guard/_/N-25un?filterByKeyWord=mud+guards&fromString=search