Removal of the back seat

I need to know how to remove the back part of the back seat that separates the seating compartment from the trunk in a 88 Lincoln Town Car. I am installing new speaker cables to upgrade the sound system and cant seem to find a way to run the cables into the truck from the seating compartment without removing the seat back.

Would greatly appreciate any help.

Thanks.

Manual says:

1. Apply knee pressure to the lower portion of the seat cushion and push toward the rear of the vehicle to disengage the cushion from the brackets, then remove the seat cushion.

2. If equipped, remove the rear armrests.

3. Remove the lower seat back bolts and the outer seat belt bolts.

4. Grasp the seat back securely at the bottom, lift up to disengage the hanger wire from the bracket, then remove the seat from the vehicle.