Dear ps131: This is entirely a surgical question and a technique question. Your PS is correct in that you cannot put any live tissue in a place where there is inadequate blood supply. Everyone's anatomy and healing is different and that may be the reason your ps is giving you this advise. You should have a thorough discussion with your PS, letting him/her know your concerns. You could seek a second opinion if you are uncomfortable.
I have a reconstructed nipple via a star flap, and it is right on the scar. I had no problems with it.
there are many ways to reconstruct a nipple; choice depends on anatomy, as well as preference of the surgeon and patient. If you have concerns, you should definitley express them before the surgery: tell your surgeon your concerns, see what the response is, and judge if it makes sense to you. If it doesn't, see about another opinion. But not every technique is applicable to every situation; for various reasons, compromise sometimes needs to be made.