Well, think of it the way he probably is, for all he knows, you are getting ready to eat him and you are fifty times as large as he is. It will probably take a great deal of time and patience to get it used to handling. It is possible that it will never calm down. This animal is a wc, so it isn't used to handling and will have to adjust.
I currently am keep two WC pines for a good friend...One is as calm as a lamb and never hisses or strikes even out of feeding response. The other however is a different story. All I have to do is turn the light on and she explodes to hissing and when I open the container, she explodes into striking. Very nasty little girl to be sure. Believe me, it is not just a display either. I have tried to calm here down for nearly a year now with no luck, but I keep trying.
I know this doesn't help (rarely does my advise help someone, it usually confuses them) but just be patient. One trick that sometimes helps is placing a good hide box in, when they are in it, "pour" the animal slowly into your hands and doen't try to manuver the animal, just let it cruise in your hands for a while, return it to the cage and just keep doing it frequently.
Good luck and be sure to get it to a vet and get it treated for parasites if you plan to keep it. With the stress of being in captivity and you trying to calm it down, a parasite load and the stress combined may be very harmful or fatal to the animal.
dc