Just checked, and they works fine, see the screenshot. They are obviously difficult to see in the screenshot, because it's static, but they are very easy to see in the sim, when they flash.
I don't know why you don't have them, perhaps there's another scenery (AFCAD, coming from a traffic package, maybe ?) in conflict. Try to check with the AFCAD program for duplicate files at JFK, there should be 2 and not more: the one from the default scenery, and ours. If you have more, remove all the extra.