[Dovecot] IMAP ACLs not working

[Seba]

Hi,

I've some problems to get folder ACLs working with Dovecot. I've
defined some folders (like drafts, spam etc.) for every user and
created a dovecot-acl file in every folder so that users can not
delete or rename these folders but this does not work as expected.

Config
=====

Debian Lenny 5.0
Dovecot 1.0.15

dovecot.conf
=========

protocols = imap
protocol imap {
  listen = xxx.xxx.xxx.xxx
}

disable_plaintext_auth = yes
log_timestamp = "%Y-%m-%d %H:%M:%S "
ssl_disable = yes
mail_location = maildir:/home/vmail/%Ld/%Ln

namespace private {
  separator = .
  prefix =
  inbox = yes
}

mail_privileged_group = vmail

protocol imap {
  mail_plugins = acl
}

protocol lda {
  postmaster_address = postmaster at example.com
  hostname = hostname at example.com
  mail_plugins = cmusieve
}

auth_username_translation = %Lu
auth default {
  mechanisms = cram-md5

  passdb pam {
  }

  passdb sql {
    args = /etc/dovecot/dovecot-sql.conf
  }

  userdb passwd {
  }

  userdb static {
    args = uid=5000 gid=5000 home=/home/vmail/%d/%n
allow_all_users=yes
  }

  user = root

  socket listen {
    master {
      path = /var/run/dovecot/auth-master
      mode = 0600
      user = vmail
    }
    client {
      path = /var/spool/postfix/private/auth
      mode = 0660
      user = postfix
      group = postfix
    }
  }
}

Folder structure
===========

(For dovecot-acl)

/home/vmail/example.com/user/.Spam/dovecot-acl

dovecot-acl contains
===============

owner lrwstiek

For me the config looks OK and I can't find an error...

When I change the dovecot-acl to "owner l" for example it seems that
this change has no effect.

Are there an error in my setup?

Seba