The pull out bumper with "bike rack" post is not designed to be a great bike rack - I guess the manufacturer has to compromise something when designing a multipurpose thing-a-majig, to carry bikes, generators, and kayaks and the such......
I had it on my old Montana Mountaineer 5th wheel. I started with a 2x4 carriage bolted to the post extending horizontally back towards the trailer. I found that to be quite inflexible though when I got different bikes as the kids got older. I then switched to hybid design where I cannibalized an older bicycle carrier by cutting off the horizontal bar that extends horizontally and bolting that to the upright post from the pullout bumper.
As other posters have mentioned, I used lots of tie down straps (racket kind) as well as bungee cords to secure the bikes so they did not bang around when travelling.
Sorry, I do not have any pictures as I do not have that unit any longer.
Take care,
Brian