Denny's factory set up. (looks like just brake and tail)
http://www.pbase.com/dennygraham/image/121297553http://www.pbase.com/dennygraham/tail__brake_lights&page=allMy not so pretty connection .... It works
...pic.... I have some shrink wrap in place to protect that connection
In my pic you might see a 4th wire. It's for the back up
Lamp I ran my two wires from the right tail,to the left side at the rear... tucked in the cross member.
Tied the tails together at the rear and ran the one wire the the switch
The two stop wires run directly to the signal switch since my signal switch had the brake feature incorporated. 7 wire signal switch. Not sure if your signal switch has the same feature.