Remote Control Car Controlled By Computer

I'm doing a project where I am rewiring a remote control car remote to work using a computer interface. I've found a few tutorials on how to do it, but they all deal with a "button" controller, where the motion is controlled by pressing buttons rather than using a "pistol grip" controller, or one with a wheel to control turning and a trigger to control acceleration and deceleration. Has anyone tried this, or does any one know if I would be able to use the tutorial linked below with this controller. I highly doubt it would work, but I would like a better opinion.

http://jbprojects.net/projects/rc/