[Dovecot] multiple namespaces, Mac OS X

[David Koski]

After installing a new server with postfix/dovecot I found that the Mac OS X 
mail client does not see email in subfolders.  It seemed to be related to the 
namespace.  From dovecot.conf:

namespace private {
    separator = .
    prefix = INBOX.
    inbox = yes
    hidden = no
}

After googling I found that I might need to add a default namespace with an 
empty prefix so I added this:

namespace private {
    separator = .
    prefix =
    inbox = yes
    hidden = no
}

Then I was able to access mail in subfolders using the Mac mail client.  
However, using Kmail I can see both namespaces, where all the folders are 
listed under the inbox at the same level, and where all folders are listed 
one level below the inbox.  I don't really want to keep my "INBOX." prefix so 
existing accounts remain unchanged.  How do I solve this?

The current dovecot.conf is below.

Regards,
David Koski
david at kosmosisland.com

log_timestamp: %Y-%m-%d %H:%M:%S
login_dir: /var/run/dovecot/login
login_executable: /usr/lib/dovecot/imap-login
first_valid_uid: 104
last_valid_uid: 104
mail_extra_groups: mail
mail_location: /var/vmail
maildir_copy_with_hardlinks: yes
mail_plugins: quota imap_quota
imap_client_workarounds: outlook-idle delay-newmail
namespace:
  type: private
  separator: .
  prefix: INBOX.
  inbox: yes
auth default:
  mechanisms: PLAIN LOGIN CRAM-MD5 APOP NTLM
  user: nobody
  passdb:
    driver: pam
  passdb:
    driver: sql
    args: /etc/dovecot/dovecot-sql.conf
  userdb:
    driver: sql
    args: /etc/dovecot/dovecot-sql.conf
  userdb:
    driver: prefetch
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
      user: postfix
      group: mail
    master:
      path: /var/run/dovecot/auth-master
      mode: 432
      user: vmail
      group: mail