Exchange Server 2003 users in one child domain cannot access shared resources from another child domain in the same Active Directory forest

Consider the following scenario:

--You have a single Active Directory directory service forest that contains two child domains.
--You install Microsoft Exchange Server 2003 in the child domains.
--You create shared resources in one child domain, such as a shared calendar or a shared resource mailbox.
--You grant access to the shared resources for Exchange Server 2003 users in both child domains. For example, you grant the following rights for each shared resource:
--Full Control
--Take Ownership
--Send As
--Receive As