KT,
One of the things that I did was I tried really hard to realize when my son had pooped in his diaper and when I would change him I would have him put the poop in the toilet.
Also when I was ready I just got rid of the diapers all together except at night until he started to wake up dry for about a week. Then if he had an accident I would make him clean it up and strip his bed and put the linens in the wash machine, etc., etc.
My son never napped so I didn't have to worry about nap time diapers, but you could try having your daughter go to the toilet before she takes her nap.
My take on the diaper at night and during nap time is this. The child knows that if they pee or poop that it's OK because they have a diaper on, we have trained them to not worry about just peeing or pooping whenever so at night it doesn't even wake them up, however when they start to wear underwear it's a whole different story, when they pee or poop it's much more uncomfortable and most children don't like it. Also they can begin to feel when they are going to pee and it will start to wake them up at night. You have to be ready for this though because it means more work for you for a little bit, but if you have your daughter be part of the clean up eventually she will realize that if she just went in the toilet it's a lot easier than all that clean up.
I hope that you find the method that works for you and your daughter.
good luck and take care,
Mel