Interoperability - SP1 and R2 Consoles
The consoles are version specific and therefore you won't be able to connect to a R2 management group with your SP1 console unless......
The following information courtesy of Michael Pearson:
1. Create a folder for ManagementGroupSessionManager if there’s not already one there.
HKEY_CURRENT_USER\Software\Microsoft\Microsoft Operations Manager\3.0\Console\ManagementGroupSessionManager
2. Create a new DWORD called DisableServerVersionCheck
3. Set the value of that dword to 1