I just lock the car using the button on the key (deadlock) and then press the button on the rs fob... That way both alarms are set..

Then to unlock press the rs fob button ( that will unlock the doors). And then press the unlock button on the key. (if you open the door before that the standard ford alarm will go off)

Bit of a faff, but that way both alarms are armed for your peace of mind. Lol