Maildir permissions on creation?

Hello.

In my configuration dovecot reads home from mysql and uses no variables within it. It uses Maildir++ storage with virtual users. I also happen to use LMTP.

I want to use a backup solution that does not involve running itself as root. Neither do I want to run it as dovecot's mail user.

And there lies the problem: dovecot creates maildirs with 0700 and files within them inherit that set of permissions. And there seems to be no sane way to control it. I think I've figured out what to patch in order to change that default, but if possible, I'd like to avoid doing that.

tl;dr: is it possible to change the default set of permissions for new maildirs created by dovecot?