F-150 remote start problems

I tried a search for theis problem and got some clarification but I still am not 100% sure what I need to do.  I am installing a Ultra Start remote start in a friends 2000 F-150 P/U (5.4L).  It does not have a transponde key but it seems to have an anti theft system.  I connected up everything and the truck just cranks

I saw something about a bypass module but wasn't sure if I needed that or not.  Is there a trigger or something I can get from the remote start unit to diable the theft system.  I guess that is what the problem is.  it got a good Tac signal but it just cranks.  If there are wires I need to connect to in the vehicle wire harness, please let me know.  The more specific about what I need to do the better for me.

Thank You very much for any solutions and inputs !!

Brian

The key has a black plastic piece on the end but the owner has had keys cut for it and they use a stock all metal key to duplicate it.  It does have the anti theft lite flashing in the light panel?

What do I need to do?

 I just figured out that a BLK/PRPL wire connected to the ignition switch is hot until you put in the key and then it goes to 0V.  The truck will start with the key in the ignition.  I am not sure how that circuit works.  When you put the key in the Voltage goes to zero on that wire and the key in ignition chime starts to ring.  I am not sure how to use the remote unit to give that 12V wire a negative pulse without grounding something that shouldn't be.

 Let me know, Thanks