cd player installation on '79 bird

Need some help here. I have a 1979 Thunderbird that I am installing a Sony XPlod cd/mp3 player in. I have removed the stock radio and have all the cars wires. The new unit is the standard 8 wire setup, but low and behold the car's is a six wire setup (apparently a very rare find). The car has five speakers (one in each door, two in the back and one in the dash), and the six wires are carrying positive and negative on a common ground. Does anyone know how to make this installation fly or know of any company in the Chicagoland area that has experience with this kind of six-wire setup?

Ok from what your telling me these 6 wires are both posetive and negative? Ok If I remeber right the bare wire is negetive and the other is positive. Connect these wires to from the door, back speaker and so on to the 6 wires. Plus go to a part store and get an adapter harness as a bridge between the car and the speakers. Dissconect the negetive battery cable before you begin. As for the power my advise is to splice into an exitsting 12volt component to power up your unit.