I agree with Doug. The repair document(s) appear to be prepared by Lippert. Clearly, Heartland/Lippert are both aware of the fault(s), hence, the repair documents exist. However, in the world of engineering, sometimes one company gives another company, (usually a supplier) whats called a "performance spec." These are general specifications which lack detail and require the supplier to provide some design work. If that's the case here, both companies could share some partial responsibility. Just a guess.
Was this RV built AND sold initially in the USA? As I understand, it's now in Canada. Without reading the terms of the warranty, there could be "across the border" legal issues which are further described the the text of the warranty.
Per the drawings, Lippert provides a part number for the repair parts. If you could get the repair parts package in full, I wouldn't have problem finding a certified welder to install them. (you should be fully reimbursed for your expenses in doing this) This isn't rocket science. You will be possibly opening a can of worms should there be additional issues, but at least you could safely move on from your present stalemate. Good luck to you.
Chum lee
