migrating to virtual domain support

[Stefan Palme]

Hi

I have a cyrus imap server installation without virtual domain support.
Some months ago I started receiving mails for other domains besides my
"default" domain, so I have usernames like "bob" (for the default
domain) and "fred.domain2" (for the additional domain domain2.com).
(The naming scheme "NAME.DOMAIN" has been introduced to avoid
collisions, in fact I emulated virtual domains this way).

This gets more and more ugly, so I want to migrate to "real" virtual
domain support. I've tested virtual domains on a test server, and
everything is fine. 

My only problem: how do I migrate the mails from the old "fred.domain2"
mailbox to the new "fred at domain2.com" mailbox? Until now there
exists a mailbox "user/fred.domain2" (I'm using unixhierarchystyle).
The new mailbox for this user is "user/fred at domain2.com" - so there
is a new mailspool directory for this account.

I guess I can not simply move the content of /var/spool/imap/f/user/fred^domain2
to the new location /var/spool/imap/domain/d/domain2.com/f/user/fred
without breaking something. 

So what needs to be done to ensure, that fred will be able to read his
old mails (and seeing his old mailbox structure) after switching to 
virtual domains and logging in using his new account "fred at domain2.com"?

Thanks and regards
-stefan-