my daughter urinates in her bedroom closet, what can I do to stop this?

[AKmamabear]

My 6yr old, will during the day, and night; remove all together or pull down and away her pants and underclothes to pee in the corner of her closet. It does not stop here, nor did it start here.
The peeing in the closet started at our old apartment where she had shared a room with her younger brother (now 5yrs), and stopped when we moved into our new house (about six months ago)..... and JUST recently (within the last two weeks), she has started to ball up shower towels in front of the toilet and pee on them.
When confronted she lies, lies, lies, and throws fits, blames it on the dog, her brother.... although I have physically caught her myself pulling up her pants after and incident. (as well as brother running out of their old room that they shared and telling me she was in the process of peeing on the dress up clothes) When she had finally admitted to it, about a week before we moved to our new house, it was because Grandma caught her peeing on the outdoor picnic table... She denied it at first, but then she said she didnt know why she did it and that she wouldnt again.
Now it has started again in our very first, $300,000 dollar home that we built with our own two hands. I am very upset. Have no tools in which I could apply to this situation.... (I have an appointment with the family doctor tomorrow; however we do know there is no "organic" reason for this, like infection, ect. Because it happens less often at night, I doubt that it is a "bedwetting" type situation, not to mention she gets REALLY upset if she herself is "wet")
Please help me, I don't know what to do to help my daughter, myself or my poor house.

[RockRose]

I'm curious what the doctor had to say.

It seems there are two ways to look at this - either she is trying to anger you,  or there is something about the toilet(s) that scare or irritate her.