Out in the real world, I was again reminded that OCS 2007 BPA can help you when you run in to problems.
I was deactivating a Mediation server but that wasn’t the biggest success I had doing that. I jumped to installing the new Mediation server, but after first step I couldn’t activate the Mediation server.
Now it was time for OCS 2007 BPA to help me, and in the report there was a hint “Windows 2008 server” but unfortunately the link to solve the problem wasn’t that helpful, so I found this solution on goog....... no I mean live.com… I hope my Microsoft contact doesn’t read this:
The Office Communications Server 2007 can be deployed in a domain having Windows Server 2008 as a Domain Controller and its a normal deployment.
But if you already have an Office Communications Server 2007 setup running in a Windows Server 2003 forest, then you need to prepare your forest once again if you add any Windows Server 2008 Domain Controller (First time). Otherwise Office Communications Server 2007 will not work correctly; some UI elements will disappear, and you will be unable to add more Office Communication Server servers or pools. To resolve this issue, you need to prepare your forest once again for Office Communications Server 2007. You can either use Office Communications Server 2007 deployment wizard or simply reissue one command after the installation of Windows Server 2008, as follows:
LcsCmd.exe /forest /action:ForestPrep
Source for the solution: http://www.ocspedia.com/Misc/Win2k8OCS2k7.htm
Conclusion: use the OCS 2007 BPA if you run in to problems it might help, and yes it’s a great tool, but still room for improvement.
BTW: after the ForestPrep I could also deactivate the old Mediation server.