external account using LDAP

[pcallahan]

I currently have accounts setup and logging onto Zimbra using LDAP (eDirectory). Our primary mail server is outside of Zimbra, so each user would need to have an external account setup and connected to our IMAP server. This IMAP server uses the same LDAP that has been configured for the Zimbra accounts. When a user changes their password it is obviously seen during the Zimbra login but the external account needs to be reset. Is there anyway to set the external account to use LDAP or at least pass through the authentication that was used to authenticate into Zimbra?