Weil ich es immer wieder googeln muss, hier endlich mal die Links:
How to Install Exchange 2007 SP1 Prerequisites on Windows Server 2008 or Windows Vista
http://technet.microsoft.com/en-us/library/bb691354.aspx
How to Create a Windows Server 2008 Failover Cluster for Cluster Continuous Replication
http://technet.microsoft.com/en-us/library/bb676403.aspx
The installation of the Exchange Server 2007 Hub Transport role is unsuccessful on a Windows Server 2008-based computer
http://support.microsoft.com/kb/952842/en-us
(watch the „Fix it for me“ 🙂 )