I got it to work.
The /disasterrecovery-Option for the Setup.exe of the exchange-server was not enough. Searching more in google finally brought the solution: Q267573.
I’ve created a .reg-File so you don’t have to make 5000 clicks when in the same situation:
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINESOFTWAREMicrosoftRpcClientProtocols] "ncacg_ip_udp"="rpcrt4.dll" "ncacn_http"="rpcrt4.dll" "ncacn_nb_tcp"="rpcrt4.dll" "ncacn_ip_tcp"="rpcrt4.dll" "ncacn_np"="rpcrt4.dll"
If somebody can tell me why the dedicated disaster-recovery-option of the setup program does not create those entries, please tell me here and now!
I will now make some tests with an Outlook-Client and then finally go home (it’s 1:30am localtime)