LDAP auth for http proxy module

[ercole77]

Hello guys
im trying to use Zentyal as replacement for my proxy server
I do not uderstand the correct / suggested procedure to use LDAP auth for active directory users.
Based on what i read in the documentation the only way to "read" users from an existing domain is to configure zentyal as an additional domain controller for that domain, am i right?
Is it possible to simple join the domain like a windows workstation?
I do not need an additional dc but simple connect to my ad users for http auth.

Thanks