A most superb how-to job has been demonstrated by Janet & Janet's Husband
. Click the link.
One point -- Their trailer is a Minuet, narrower than yours & mine by 6", so take note of 'part 7' where you don't have to modify the center section.
Second point -- An Airstream dealer can order the part (nope, they aren't interested in doing maintenance on our vintage units!), but Andy gives good service and contributes greatly to these forums. You might just want to ask around for prices anyway. You'll probably have to install it yourself or know someone handy. (I bought mine from Andy at InlandRV.com and will be putting it on over this winter.)
Third point -- The trees are bare and winter is close in following. Bummer - bummer - bummer!!! ;-)~
Fourth but not least -- Welcome to ASForums 'balrgn' and many happy returns to this site!!