Thanks for your quick reply!
This shoud fix my problem. I'll try to implement this on monday.
But I totally forgot one special case:
There are some users with more than one mail address (mails are aggregated to one mailbox) and their imap username was set with their first activated address.
for example
facilitymanagement-munich-2@example.org (first address) and
john.doe@example.com (second address) lead to
33440055-33-0-facilitymanagement-munich-2 and your solution would make
facilitymanagement-munich-2 out of it and so on...
Our hoster accepts all valid mail addresses als username in his (very ugly and outdated) webmailer. So John Doe was used to login as
john.doe@example.com. I think
john.doe would be ok too, but
facilitymanagement-munich-2 is not 'optimal'. There are also a few persons who changed their surnames due to a marriage. Now they would have to use their old name again. To prevent this we would have to delete and recreate every affected account. Unfortunately there is no other way to change the imap username.
Is there any
simple supported suitable solution for individual 'username translation'? If not, I have to go the hard way (backup-delete-recreate-restore a lot of accounts).