My car is a 2002 Ford Mondeo after much messing around and not getting anywhere fast i spoke to a few people in the know and this is to help people who are in a similar situation to myself (that being not having any idea about how to rewire things and set the software up).
First i took the steering wheel control apart for the radio and was faced with this board.
I then spoke to CDRskull on mp3car and he sent me back this wiring diagram. This gives the points to solder to from the car end.
Next you need to buy a usb joypad, it doesn't matter what it is, as long as it has enough buttons. download a piece of software called joy2key from this site.
http://www.electracode.com/4/joy2key...%20Version.htm
This software allows you to very easily put hotkeys onto the buttons you need. and because you press the button on the joypad and not have to mess around with guessing its childs play. I checked it worked well with centrafuse before i started taking things apart. after you do, you will be faced with a board looking similar to this.
I then went onto mp3car again and Gospeed.Racer helped me out with the wiring diagram for this. this photo only shows 4 connections but it is the same principle for all buttons.
As you can probably see from the photo, one side of each of the buttons follows a track, the other side is connected to the outside of the board. you need to connect a wire from button 1's positive side on the track to the positive part of the button on the other board, repeating this step for all buttons. then connect the one common point, which in the case of this diagram is the black point, to the common on the other board, which on the other photo is one of the 2 blue points. The joypad board is relatively simple to the car one, as even with my limited knowledge i figured out what was what fairly quickly.
I have been advised that 20 or 22 gauge wire is best for the job, however it doesn't matter too much if the guage is slightly bigger or smaller.
Once that is done, put the board back into the car, plug the usb cable in and set it up on joy2key. then go to the Centrafuse hotkey settings in the settings menu, choose what you want each button to do, by finding the relevant action you want, clicking on set, press the red button and then click the button on the steering wheel control, then repeat for the actions you want for the other buttons.