Lets wait for someone who has done this and has some answers. I am very excited about the question.
Being a painter I have never encountered this question or job. I would tell the homeowner to just clean it with TSP or that new chemical, but if you wanted to change the color, that is something entirely different.
There has to be a primer that would allow this to happen.
You know, if I was asked this question by a homeowner, I would excuse myself and go to my cell and dial my nearest Sherwin Williams and ask them this question.