Can new telephone central (VOIP) use GW's LDAP address book?


As the title describes, there is a new voip phone installation going on. The phones are capable of 'talking' to an LDAP server for phone number.
How should our GW system should be 'prepared' for these new phones, if we want to use the LDAP server lookup for phone numbers.

Suppose we have properly done the initial security settings to allow the phones to 'login' into the LDAP server (which is our eDirectory). Where should these phones look for 'data' in the LDAP server? Is it searching for eDirectory users in the LDAP server, or looking for GroupWise users? Or because it is and LDAP query, it is looking for entries with some certain attributes (cn, phone, etc)?

Let's suppose we want to use this method (phone address book on LDAP) mostly not for our internal users, but for other contacts, who doesn't have GW or eDir account in our servers. Do we have to create individual entries (I suppose GW external entities) for every single contact, and configure a phone number, so the telephone's could pick it up from the LDAP server?

I have made some searches here and also and good old friend google, but mostly I have found topics about how to authenticate through LDAP. This has nothing to do with authentication. We just want to use GW to give us phone numbers on our new voip phones.