They look very nice, I assume your trailer has a awning rail. Contact the vendor and ask if they just slide into the rail.
I just read the FAQ and it normally attaches to the rain gutter, I bet you could make it work. Find a mount that slides into the awing rail and attach from there. Good find.
Looked again in the first picture the little camper looks like it is attached to a awning rail.
Jim N5TJZ Air# 174
2012 International Serenity 28
2005 Safari 25 SS Traded
1968 Globetrotter Sold
2011 F150 Ecoboost