[Dovecot] Recover mailboxes

[Jordi Espasa Clofent]

HI all,

Some time ago I've user at domain.com in maildir mailbox with their own 
mails, their folders, subfolders, indexes files.. etc

My server was missconfigured and I've rebuilded all SMTP; I've recreated 
all the mailboxes with same names that before. Of course, the problem is 
the content of these mailboxes it's not the same. So, the idea is:

add all the contento from user at domain.com (old) mailbox to 
user at domain.com (new) mailbox.

because I have got a complete copy of (old) mailboxes and their content.

¿How can I do it?