Finally fixed
I went to the dealership today, and they took my car in immediately, asigned a tech to it, and they re-surfaced the rear rotors and re-greased the brakes again. The problem seems to be gone. But we'll see after a week. I really hope that the problem doesn't appear again with this set of pads in the back after 6 monthes like it did when this set of pads was installed in December.
They gave me a car wash too, and my service rep wrote me a letter to thank me for the opportunity to right the problem and for me to call him if anything wasn't right.
Arrowhead Honda in Peoria, AZ - great place for service. They are the only Honda dealership in the Phoenix area with a President's award.