True its very difficult but not impossible. Every year 1 or 2 IMG's do it. With a PHD I think you would have a leg up. The best thing you can do is decide that you are going to be a plastic surgeon and then give it your damnedest. Look at the number of program chairs and program directors there are who trained in foreign countries entirely. They probably had to go through hell to get there but its not easy for anyone.
There are 2 paths:
1) combined/integrated: match straight out of medschool
2) General surgery followed by fellowship.
It used to be that the match rate was 80-90% for people who would be board eligable in general surgery and only 40-50% for med students trying to go straight in. Now the match rates are similar. If you are positive that you want to do plastic surgery then I would at least apply to the combined/integrated spots. Make sure you do a handful of away rotations at places that interest you as this seems to be a very important factor in the match. I would also apply to the general surgery programs that have fellowships attached. Its always easier to get a fellowship at your home institution. At any rate best of luck. I will be rooting for you!