[Dovecot] Mail_quota plugin and LDAP on Dovecot 1.2

[Victor]

Hi, I'm new in this List, but I have 6 years using
Dovecot on my debian from etch,lenny and now squeeze

Package: dovecot-imapd
Version: 1:1.2.15-4
Tags: squeeze

-- System Information:
Debian Release: 6.0
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-5-amd64 (SMP w/24 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages dovecot-imapd depends on:
ii  dovecot-common                1:1.2.15-4 secure mail server that supports m
ii  libc6                         2.11.2-10  Embedded GNU C Library: Shared lib
ii  libldap-2.4-2                 2.4.23-7   OpenLDAP libraries
ii  libssl0.9.8                   0.9.8o-4   SSL shared libraries


the quota_imap plugin not working when I use against MailquotaSize Attribute of  LDAP users. 
this setup works perfectly on lenny and dovecot-imapd 1:1.0.15-2.3  but on squeeze dovecot-imad 
1:1.2.15-7 doesn't work, the service is up, but The quota does not display. In logs nothing happens

the configuration in dovecot.conf below

protocol imap {
  mail_plugins = quota imap_quota
}
protocol lda {
     mail_plugins = quota
}

 userdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
  }


the configuration in dovecot-ldap.conf below

uris = ldap://server-ldap.com.ve

auth_bind = yes

ldap_version = 3
base = dc=dominio,dc=com,dc=uk
deref = never
scope = subtree

user_attrs = homeDirectory=home,uidNumber=uid,gidNumber=gid,mail=Maildir,mailQuotaSize=quota=dirsize:storage
user_filter = (&(objectClass=posixAccount)(uid=%u))

pass_attrs = uid=user,userPassword=password,homeDirectory=userdb_home,uidNumber=userdb_uid,gidNumber=userdb_gid
pass_filter = (&(objectClass=posixAccount)(uid=%u))
This is the same configuration in the 
6 last years. So, I would really appreciate if give me a hand which are more than 15000 
Users who administered easily taking the quota in the LDAP attribute. 
and I want to keep the scheme. 
Thz
Victor Onate
Usuario Linux