External LDAP auth and password expiration

[uptimevarese]

Hi all,
I recently completed a new infrastructure based on linux pdc, ubuntu 10.04 with ldap, samba and gosa to manage accounts, and zcs 6.04 as shown below on frontend to manage emails.

Release 6.0.4_GA_2038.UBUNTU8_64 UBUNTU8_64 NETWORK edition.

Since I need password expiration and zimbra connects to ldap on backend server to authenticate users, I need to know what appens when passwords expire.
Is this a managed stuff?
Suppose my user bob has an expired password and logs himself on his windows workstation, he will be prompted to change it, allright.
But suppose now that bob, my user with expired password, logs himself on zcs webmail. What happens?
Will he be granted his access?
Will the access be refused with an expired password error?
Will the access be refused with a generic user/password mismatch?
Since I have disabled for users the ability to change passwords because otherwise changing password from zcs webmail will break the password syncronization, I need that zcs may inform user to go to gosa web page, to login and to change password to continue.
Thank you in advance.