Our objective is to enable users from different forests to utilize contact objects in the central/resource forest for instant messaging services using OCS. We have delayed deploying LCS, choosing instead to wait for OCS. The contacts from 20 different Active Directories already exist in the central forest via an existing LDAP synchronization tool --not Microsoft Identity Integration Services (MIIS)-- that we prefer not to replace because that would be a big project all by itself . Microsoft indicates in the white papers for OCS that MIIS is a prerequisite for achieving what we want to do. Is that the case, or is there any way to accomplish this without MIIS in place?
In early testing populating the requisite fields on the contact objects from the associated users allows us to successfully enable the contacts for IM, but the users in the trusted AD cannot login to Communicator with Kerberos/NTLM (default) for authentication.
