[Dovecot] dovecot + ldap + quota

[aza zel]

hi....

i using dovecot 1.0rc26 and i started to configure quota plugin but i think
its not working fine.
i configure like suggested in http://wiki.dovecot.org/Quota

in dovecot.conf:

protocol imap {
  mail_plugins = quota imap_quota
}

plugin {

  # 10 MB quota limit
  quota = maildir:storage=10240
}

in dovecot-ldap.conf:

user_attrs = homeDirectory=home,uidNumber=uid,gidNumber=gid,quotaStorage=quota


if a mua send a attach near 9MB i receive a message tell me that the server
don't have more space, but if i attach files of 2MB this messages are
sending ok, and the cur directory of this user have 15 MB.

another question: in ldap entry, the attribute quota are the attibute that A
represents the quota on a mailbox,
   ¿so why i put 10MB as limit?

uota = maildir:storage=10240

¿this value is for all "entryes" or the quota limit is the entry quota
limit?

i you can see, i not understand how dovecot works with the attribute quota
in ldap entry; ¿can anybody explain me this?

Thanks in advance!!!