Unfortunately I'm not a MOD writer, I suggest posting in the MOD requests forum http://www.phpbb.com/community/viewforum.php?f=72
That's all these fellows do and they are very proficient, If it can be done, they can do it.
On the backups I suggest using phpmyadmin to make any database backups, it can be accessed via your hosting control panel. I never recommend using the phpBB backup utility.
Also be sure to keep complete file backups.
The auto update package has been greatly improved for the latest version, even if the zipcode 'hack' won't merge correctly it shouldn't be a large job to re-add and I feel the update will be worth the effort.