I saw this mentioned in a post back in November. However, I didn't see a solution and it sitll seems to be an issue. I also searched the Bug List, but didn't see anything outstanding for this problem.
When using the Zimbra GAL as an LDAP address book with external email clients the Name field shows up as the user's email address minus the "@domain.tld" part, instead of the Display Name field. This happens no matter whether the Display Name is set to "auto", or if it is manually filled in. I've tested this with both Thunderbird and Outlook 2000 so far.
Just wondering if this is a known issue that is on the "to do" list to fix.