Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Communicator] "EnableAppearOffline"=dword:00000001

; sometimes this might also be needed ; [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Communicator\Policy] ; "EnableAppearOffline"=dword:00000001

; ref: http://technet.microsoft.com/en-us/library/dd572602(office.13).aspx