viper 350hv starter interrupt relay

I'm installing the 350HV on my car tonight and I just have 1 question about the starter interrupt relay that came with the 350hv package. I know the negative signal for the coil will come from the main alarm unit but I'm not sure about the 12v signal. Do I hook it up to a constant 12V output or to the ignition wire? I got confused because I searched and all I found was saying to hook to the ignition wire which is only hot when the ignition is on but on the manual, it's saying that the signal from the brain in constantly supplying (-)ground to the relay when the system is armed. So if I put the 12v wire for the relay to the ignition wire then the relay will not work if I take the key off. Sorry for the newbie question, I'm good at electrical but first time installing alarm today. Thanks!

Ok thanks! I thought the starter  is always disabled when the alarm system armed, it only disconnects when somebody start it.