Hmmm, looks like you might two separate problems..
Is this the trick the dealership was talking about?
http://www.youtube.com/watch?v=XSASOhHi_tsRemember, there are two different contacts, on the parking light bulb - one for parking lights and one for the brake light on the bulb socket.
Have you changed the front signal/parking light bulb?
The bulbs have two separate filaments, one for the signal and one for the parking light.
It is possible to have one burn out and not the other..
I read you other post as well, I would take the tail light out and trace that wiring harness that is usually protected by the bumper.. Since you no longer have the stock bumper, maybe that harness is not secure and rubbing somewhere.
Good luck!