Steering wheel controls mod?

[pontiac6ksteawd]

I have been trying for over a year now to get my CD player steering wheel controls to work. When i install the control unit, the ON/OFF button, the one to the right of that, and to the left, work. But none of the others do. If I install a regular steering wheel control pad, all the buttons work, but I am wanting the CD controls. Do I have to replace some box or something in line with the steering wheel controls that may be diferent from tape deck to cd deck?