I still say free will can be acheived once one knows themselves. If once knows themselves they can control their own path, control their emotions, and perspective.
Imagine yourself riding in a car on autopilot. Your not choosing when your not steering, you are being determined by the car. Imagine the car as being natural law and nurture guiding you where it would naturally go.
Whats from stopping you from taking the steering wheel? Your subconscious, conscious, and will. If you are self actualized you can steer. If you know yourself, you don't aways have to take the narual course of keeping that crappy job you hate, or you could make the job better yourself. You could simply look at the job in a new perspective also. You are not being determined anymore, you are not being oin autopilot. Autopilot is ignorance. You are now what Nietzche would call an ubermencsh who does not go along with "the crowd".
As spock said "there are always possibilities", there is not just one possibility in nature, and not just one in nurture. We have choices, I believe we can stretch our minds to determine ourselves -- control which law determines us, thus freewill.
That person could be determined to have free will. This argument has now became circular, a paradox. Perhaps those who have free will have it, those who do not, do not. Its relative, subjective.