My 18-month old started to pee in the potty nearly with no trouble, so at home we left her with no diaper(undies or naked butt) and potty around, so she can go when she has to... but poops took few more days or nearly a week later... had to have few accidents before that and never was mad with her, just explained calmly to her, that the poop goes to potty and not floor or pants... and she has gone both to potty for more than month now... of course sleeping and out of home we still need diapers, but at home all poops and pee she does in the potty... and i really am so happy over that!!! :)
but is your daughter going to big potty or little one? if the little one, then you could just keep it around so that she can go as soon as she feels the need for it... although she is pretty big to understand and the problem rather is that she is used to do it in a pull-up and that's why she does so... so i guess best solution for you is to just talk to her calm, where the poop goes and keep using underwear... i know is messy, but is less confusion for her then, as that way is always same - always just undies and everything goes to potty... hope it helps... :)