Biting is really hard because it's a trust issue. In a very intimate relationship. But it's not reasonable to expect him to learn in one day. If you are being firm and consistent he will get it. I agree that some support from Dr Newman is always good. but also some patience. I dealt with biting and it wasn't an over night thing. And things needed to be readjusted every time my son got new teeth. Because he didn't know what to do with them if they weren't there the week before.
He did get it. And your baby will too. Perhaps some infliction of emotion on your part would help. I know I think it really helped my son know things weren't OK because he could tell I was upset. I couldn't keep that from him when he bit me. I was also anticipatory about it. Always ready to unlatch.