I would suggest you call the TM factory and get their advise. I'm sure they are the best to help you with any questions you may have about updating or replacing anything in the TM.
I would also suggest you take a look at CampingWorld... they also have a website online.
I have no experience updating a TM, so I'm sorry but I am no more help, but if I were to consider such a project, that is what I'd do. Good luck!
Have you looked at the How To & Modifications Section here yet?
http://www.trailmanorowners.com/foru...e=2&order=desc