[Dovecot] Migrating from Courier-IMAP to Dovecot

[Andreas Mimz]

Hi!

I'm currently trying to migrate from courier-imapd to dovecot... 
Unfortunately I'm experiences some difficulties here...
Since I don't want any user to notice the change of the server backend 
I've tried changing the namespace in dovecot.conf to

namespace private {
        separator = .
        location = maildir:~/Maildir
        prefix = INBOX.
        inbox = yes
        hidden = no
}

With this setting almost everything works fine! Almost... ;-) 
Squirrelmail won't show 'INBOX' on the left side of the folder tree... 
If  I configure dovecot without the 'INBOX.' prefix it works fine in 
Squirrelmail, except that all other eMail clients show all sub-folders 
as a sub-folder of root and not the inbox...

root
\- inbox
\- sent
\- trash
\- drafts
\- private
\- spam

instead of
root
\- inbox
|  \- sent
|  \- trash
|  \- drafts
|  \- private
|  \- spam

any Idea what could be wrong?
I've read the wiki about the courier-migration and also tried the 
conversion script ... but something is wrong I'm afraid...

thanks in advance,

Andreas