First Class email with Barracuda Spam Filter 300

has anyone every used First Class Email with a Barracuda Spam Filter 300? I am trying to figure out a way to LDAP the users from the First Class Email server to the Barracuda Spam Filter.

I have enabled LDAP on the First Class Server but not sure what to select on the barracuda as far as server type? There are 5 choices - active directory, domino directory, novell edirectory, openldap and other.

also what would the Bind DN (username) be for the first class server?

basically i am trying to just get the valid recipients feature working on the barracuda so it can reject emails based on if user exists or not.