[Dovecot] Quota to use limits from LDAP and usage from FS

Hi,

I'm new to Dovecot (switching from Cyrus). I'm using Dovecot 2.1.7 from Ubuntu 13.04. Maildir data is stored on a Linux ext4 filesystem with quotas.

I would like to use mail quota in a way, so that the usage values are taken from the filesystem's quota system by the "fs" backend, while the per-user limits get read from LDAP. Due to debugging messages, it's my impression that reading the limits from LDAP works quite well when the user process starts, but when IMAP access actually takes place, the fs backend uses the filesystem's soft limits.

Can anybody confirm this behavior or is there a way to achieve what I intend?

-frank