dear friend. thanks for sharing your problem.
first of all i would say its not a problem
.with small children you have to be very patient. first of all you have to talk to her when she is in good mood affectionately,asking her why she doesnot want to go to toilet.?is she scared of anything there?or she feels alone there?etc..such type of questiones when replied by her will make you understand what is the hidden cause.but remember its not easy you have to ask numerous times numerous days to get the answer from her.you said she does pass stool that means its not the constipation
problem. its related with the place.also supplement her diet with plenty of fruits and vegetables and plenty of fluids.this should help.thanks