Chapter 10 Install and System Administration for FortiOS 5.0 : FortiCloud : Registration and Activation : Registering and Activating your FortiCloud account : FortiGate 600 to 800
  
FortiGate 600 to 800
For 600 through 800, FortiCloud registration must be done through the FortiGate CLI Console.
Devices beyond the FortiGate 800 do not support the FortiCloud service.