Does RMS require any schema changes in Active Directory?
For RMS to successfully expand the group membership that is specified in the publishing license across forest boundaries, a contact object must exist in the local Active Directory forest that represents the group that is in the remote forest. RMS can query the attributes of the contact object and discover that this object represents a group that is in a different forest. For RMS to do this, Active Directory requires the Exchange Server 2003 or later schema attribute msExchOriginatingForest. This attribute is installed by default in the Active Directory schema if you have one server running Exchange Server 2003 in the forest. You must have this attribute in the forest of each Active Directory schema that will be participating in RMS. If you are not using Exchange Server 2003, you can install the schema separately into your Active Directory structure by using the RMS Administration Toolkit.