Hi R.,
there may be a combination of contributing factors.
What if you continued on your 'no pull ups' at night strategy - once you get a waterproof mat for her to lay on?
Waterproof bed mat options: http://tinyurl.com/waterproof-mats
(As you can see, squillions of other parents deal with this same issue)
She's been weeing in her pants (the diaper) since she was born, so this is comfortable and she needs to learn to wake and then GET UP.
I repeatedly remind my son that if he wakes at night he should go to the loo for a wee - as that is why we wake at night - to go to the loo!
With some role playing fun, practice being asleep, waking and then RACING to the loo.
What if you gave her a hefty dose of self confidence? Tell her she can do it, and will get better and better. No OJ until it settles (blame any juice or non-water drink as 'causing' night wees too)
Does she wake at a regular time? I'll bet the pants are WARM - ie they wee on waking. Get in her room just before her waking time and help her to fly out of bed in time for a few days.
Tell her to call you for help (It'll only be for a while) and help her - she may be scared of the dark - a night light? A special 'toilet torch'? Just ask.
Do you have a trampoline or mini tramp? Bouncing on it for 10 minutes at a time can really strengthen her pelvic floor, giving her more control and wait time within 2 weeks. (and yes, YOU TOO! Unbelievably effective tip for Moms - I no longer needed to get up at night myself, nor worry that I was getting diabetes as I was going to the loo all the time, LOL)
One last idea to consider is food sensitivities - additives, colours, preservatives, even natural ones such as salicylates in strawberries and such are wee-producing in sensitive kids (perhaps as a 'build up'), and weeing gets it out of their system.
Check out:
Is this your child? http://www.drrapp.com/
Fed up with Food Additives: http://www.fedupwithfoodadditives.info/
Good Luck!
You'll find a way forward, take a deep breath, it doesn't have to happen today - strive over the next month together to introduce some new changes WITH her - together as a team. You'll come out the other side stronger. There is nothing wrong with her, or YOU.
C.
http://www.tribalbaby.org/