Backup method mail encrypted with mail_crypt Per user

Hi,

What would be a good backup method for mail stored encrypted with mail_crypt per user(folder). As the administrator does not have the key (the user has)

i'm thinking:

• the user must backup his/her email via the mail client, but as an admin you want to be able to restore mail when needed on the server itself or on a new server.

• the admin creates a backup of the vmail folder per user (is all the necessary crypt information in it?) so when restored on a new server, could the user read the emails with his/her password? is it just a matter of restoring the vmail folder?

in other words: what would be needed to be saved in order to restore to a new server

any recommendations on this topic?

Kind regards, Zjemm