Sounds like you've been studying a lot of wiring diagrams. I have not so I could be wrong in this next post but here's an idea. What if you were to run your own wire from the "start" position (I believe itht e ignition 30 circuit?? maybe 15l??) straight to the starter relay which I assume is to the RCM?? Thus bypassing the immobilizer (Volvo speak). Makes the car easier to steal, but also easier to start. I think you'll be keeping your eye on this particular car...

Justin