A.W.
Hi J.,
I had the same problem with my daughter when she turned two. She just experimenting. My daughter did it quite a bit more then twice. We couldn't figure it out. Everyone that I talked to said that, it was an attention deal. We gave her more attention but it wouldn't stop... She did this for a good 6+ months. I had tried to put her in those body suit outfits, it still didn't work. She learned quickly how to unsnap them and pull them off.
I would suggest that if she's already willing to go into the potty, then it's time. I gave my kids a treat every time they went #2 in the potty. It seemed to really help me out. I know most people would disagree with a small cookie, but what ever works right... I'm sure your little darling is bright so talking to her in a sturdy voice tone, when she "paints" should do the trick.
Buying "big girl" underwear should also help as a goal. Positive reenforcement with how "grown up" or "extra pretty" she is, would be a good incentive for her.
Hope your trouble ends soon, and that I was some help, but most importantly your not alone in this!
Take care,
Ang