If he goes to a corner to do it, that's a sign that he is conscious of his needs and able to control them. It may be just that the sensation of going on the potty is so different that it makes him uncomfortable. I'd definitely offer privacy. I'd also try putting a diaper in the potty. He can sit on it and have the experience of going on the potty without the weird feeling.

It sounds like you're doing a great job. smile