We have Exchange 2007 running on a Windows Server 2003 x64 box. I would like to implement Cluster Continuous Replication (CCR). I would like to build another Exchange 2007 server running on Windows Server 2008 x64. I know that Standby Continuous Replication (SCR) requires that the source and target nodes be running the same OS but as far as I know in CCR this in not the case. My question is can I just install the 'Passive Clustered Mailbox role' on the new Windows Server 2008 box? Are there any configuration changes that need to be made on our Active Exchange Server to allow it to replicate? The two Exchange nodes are in the same domain but in different sites. We are also utilizing the Edge Transport Server Role in our Active Exchange setup. If there is another type of replication that you think is better I am open to suggestions. My main goal is to setup a failover server for disaster recovery.