When I became pregnant, I didn't intend to wean totally unless my daughter was ready but I did want to night-wean. She was probably 26 or 27 months at the time and was very much used to nursing to sleep. I started letting her nurse but unlatching her before she was entirely asleep....of course, she didn't like that at first. I would sing to her and cuddle her to sleep and later I started making up bedtime stories. As she became used to the new routine, we phased out the nursing until she wasn't nursing at all-- we just used singing, cuddling, and stories. It was almost like a dance-- I would encourage her then wait for her response then we'd go a little further.
That said, I'm pregnant, so my milk was changing and that may have played a role in her willingness to stop. It wasn't long after nightweaning that she weaned herself totally, without any encouragement from me. So I would say that you can try slowly changing the routine but if it's causing prolonged stress and making you and your child miserable, the timing isn't right yet. Every baby learns to fall asleep without nursing at some point
I wrote a little bit about our experiences on my blog--
http://domesticdissident.blogspot.co...ning-path.html
Maybe it will encourage you a little. Good luck!
prufrocks_lady