2002 Tundra Remote Starter Equipment?

Long time customer asked a favor today. Wants me to setup remote starter (RS) on his 02 Tundra. He claims a friend hired a tech to configure Toyota's factory components to preform RS function with the vehicles existing equipment (no starter kit required). With all of the electronics onboard, I guess Toyota's OEM tech's configure jumpers or something so the auxiliary button on remote could then utilize factory remote start option. Can that be done, or do I need to get him an aftermarket kit? How do configure the factory settings to save him dough?

Thanks,

        To whom it may concern, 

     hey bro there is no way to help you out on that one the cheapest way you could go is to do it the aftermarket way and well thats the only alternative or if you might want to buy a product that  Directed Electronics sells and dont mind asking if its capable of interfering witht the toyota oem system which is still doubtful .by the way ive only seen that directed works with ford and many of the chevrolet factory alarms.but hey it never hurts to ask.

email me and let me know what your resolution with your customer is or what he decided to do .but if its better if you do sell him an aftermarket kit better.