Attaching aluminum skin to trailer frame?

Hello- Newbie here. Have done lots of reading and have a plan for a 5x8 TD. I want to build it similar to the CampInn profiel (i.e.- with rounded from and rear corners). have not been able to figure out how CampInn attaches the aluminum skin to the trailer frame, specifically along the front and rear. Along the side I am guessing they use standard aluminum trim, but what do you do at the front where the skin curves down and into the trailer frame? Don't know if this is clear, but this seems to be the one thing I can't visualize.
In case you are wondering what I am talking about, what I want to build is somewhat similar to this post on eBay... http://cgi.ebay.com/ebaymotors/ws/eBayI ... 4561466732
Thanks for any help for a newbie!
Greasy

Thanks for any help for a newbie!
Greasy