In looking at the brochure, and reading your request, I am unsure what it is you are trying to do. Do you have the awning on the camp-side? What side are you trying to tarp? Do you have a picture of the rail to which you are trying to connect?
2019 Minnie Winnie 22M on an E-450 frame
Well, I don't have a good picture but good is from a few weeks ago when I was installing a soft starter but you can see the rail on the left side.... that is the driver's side.... that's the side that I'd like to put some attachment thingies so I can tie a tarp n steak it to the ground to keep the sun from hitting the coach from west side, as I ll be facing north at burning man next week... it's a straight groove without any round cut outs for like the other system...forgot what they call that..... any way, if you know what system I have and where I can get inserts to be able to tie some string/,ropes thru....