We would like to share calendars between two different organisations. Company A is the initiator of this project and wants to implement Micorosoft Federation Gateway(MFG). Company A has Exchange Server 2010. Our company B has Exchange Server 2003. In the requirements of MFG I have read so far, it is required to have a 2010 CAS server.
Is it possible to implement only a 2010 Exchange CAS server in our Exchange 2003 environment and to make MFG work between company A and B this way?