Could you better explain what you'd like to do? Trying to manage the Zimbra configuration through Gosa, modifying the LDAP records, seems to be quite hard to do. Just look at the changes needed to the
Open-Xchange configuration and try to figure out what could happen at the first Zimbra upgrade.......
I think that the best way should be to talk to Zimbra through the SOAP interface.
No problem instead, if you simply want authenticate the Zimbra users against the GOSA's Ldap