My advice would be to save the code that is currently executing by using IFI Device Reader found here:
http://www.ifirobotics.com/docs/device-reader.zip
You won't have source code from it, but you will have an executable code that in case you need to you can reload it back on the RC.
Do a trace back of all the victors, and spikes do see which pwm's, relay's, digital I/O's and analog inputs are in use and for what purpose.
Do a trace back of all the interfaces connected to the OI, any custom switches or dials will needed to mapped to their ports and functions identified.
Lastly download the default source code from IFI and begin editing with that.
http://www.ifirobotics.com/docs/frc-code-2007-8722.zip
Or for the Camera Support:
http://www.kevin.org/frc/frc_camera.zip