I've obviously never done it - my SIL had hell with my nephew - he is 3 & 3/4 and has only JUST been put in underwear full time as has gotten over his 'toilet phobia'. Sounds like he was bit like yours, totally knew what was goig on and didn't communicate about it, would go in his nappy, would go and HIDE when he had to do a poo and afterwards, and chucked a tanty even seemed scared of the toilet. They tried bribing him with lollies - that prob would have worked earlier except that he is in care at my parents and my SIL parents as well and 3 different locations did not make for consistency. I was watching a show the other day called the Dr's and they were talking about toilet training and one of the things they recommended was putting toddler in undies and when they have an accident not berating them or punishing them or anything, but getting them to assist in the clean-up so they have to deal with/understand consequences. I don't know if I would use that or anything (am not looking forward to TT in the years to come) plus sounds messy, but apparently some parents sweared by it so ? ?
PS - Oh, and this is gross - the way they finally got him in undies, was by letting him pee outside on the lawn instead of in the toilet (at first) so he could 'GO' without having to face the dreaded hole.