I want to exchange free/busy-information between 2 Exchange 2010-sites so that Outlook-users at each site can see free/busy-information for users at the remote site. I know that federation services via MS Federation Gateway can be used for this, but I want to set this up directly between the sites, NOT going via the MS gateway.
How can this be done? All trafikk between the 2 sites is tunneled and necessary ports can be opened in the firewalls. I am not looking for trust between the AD-domains, I only want to exchange free/busy-information.