ok then, first off I am no expert. There are those here who I believe are, and I am sure they will give you the support you are after in time. Also, while I have seen these birds, I have never owned one and any advice I may give would be what I obtained from others. So, I cannot provide specific advice on your bird.
In general however, I have been keeping birds for 30+years. I generally feed them my right index finger, which is covered in deep scars, and try not to show any pain or fear. Well, not always
Your bird does have an oversized powerful beak, if I remember right, and reading the bird is key.
Have you read through this:
http://trainedparrot.com/Taming/I have read half a dozen or so sites recently in depth, and I think this site has the best information and is easy for me to follow and understand. I have low/no opinion of the "pay" sites. You can find the same information online for free as well as additional and better (imhop) insights and techniques.
Than being said, my experience has taught me patience, repetition, then repeat. The is no short cut, reading, learning and understanding are key, then do it all over again and again and again. I would begin by researching and learning all I could before I got a bird, but it is not necessarily a game stopper. It simply limits your options, and possibly the outcome or your training. With effort and following the lessons in the /Taming/ site, your situation will change. Maybe not is hours or days, but in the weeks to come.
Personally, none of my birds bite, all will let me hold them on their backs except one, etc. At one point though, I had a lovebird. It would let me hold it and would eat from my hand, but it was not happy about it. It never got any better with me. Now it lives with another lovebird at a friends home, and is as tame as a kitten. Why? I have no idea. Like I said, I am no expert.
Please try to be patient. I am confident your answers will come. In the meantime, Google is your friend.
Dave