I don't think that nipple stimulation can truly happen with the pump. I think it takes hours and hours at a time, sometimes days/weeks for it to work.
ANDDDDDDDD if it DOES work, it really only means baby was ready to come anyway.
I've had both my babies way past due and don't expect this one to be on time either. We tried it ALL. Everything. Anything. 41 weeks I was induced for various health issues and had both girls within a few days. Good luck.