The wiring is shown at:
This can be determined by using a multimeter with one probe on a pin (or wire), check each corresponding pin or wire the Ohm setting. You will notice a dramatic drop in resistance when you hit the right pin. Make a drawing of the din plug and note the wire on the diagram.
I'm afraid you may have to open them up. The information you're asking for would only be available from the manufacturer and they usually only provide schematics to authorized service centers. If you were under the impression that you were in contact with the manufacturer I apologize, you can email***@******.*** for a refund at any point.