[Dovecot] default_mail_env and IMAP server directory in client

[Dirk Essl]

Hi,

I'm currently installing a dovecot Server to be a replacement for an 
uw-imapd.

I dont want to touch the clients configuration, because I have too much 
users...

Situation is the following: the mbox files are in the users 
homedirectory (~/MailImap), automounted via nfs
In dovecot.conf I've set
default_mail_env = mbox:%h/MailImap:INBOX=/var/mail/%u

It works perfect without a value in Firefox' setting 'IMAP server 
directory' but in all clients tis is set to '~/MailImap' so it doesnt 
show subfolders

I already tried to symlink various things in the MailImap directory and 
different values of default_mail_env, but I cannot mak it work.

Any suggestions?
It would help if dovecot could discard the IMAP server directory setting 
of the client, but I am not a programmer and dont know where to look in 
the source :-(

--
TIA
dirk