VBoxManage setextradata "NameOfTheVirtualMachine" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/remotedesk/Protocol" TCP
VBoxManage setextradata "NameOfTheVirtualMachine" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/remotedesk/GuestPort" 3389
VBoxManage setextradata "NameOfTheVirtualMachine" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/remotedesk/HostPort" 3389
$ VBoxManage -startvm "Windows XP"