Yes Ray, he was correct about the tubing in the wall and roof sections. Did he say anything about any wood being used in there? In mine, I had to replace the 1.5" wood that had been rotted, with 1" of aluminum tubing, and .5" thick wood strips simply added in there as a filler to fill the gap that would have existed had I only used the aluminum. I imagine they're simply just using the aluminum tubing now tho which is a 1x1 square tube. If you would like to see what I'm talking about, you can see a good example of what exactly's in there JD was talking about on my web page.
http://members.aol.com/br768
Just remember, you probably don't have the wood in there, so you'll have 2" of aluminum tubing to screw down into. Though you can still use 2.5" screws as they will simply get a better bite on the last layer of aluminum in the bottom of the bottom tube, and go harmlessly down into the styrofoam in your wall section. If you use stainless steel screws, be sure to drill your pilot holes just the right size as stainless is very brittle as you well know. Hope this helps!
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