I used to do this when i was little!! haha. once my mum asked me why i did it and my cheeky answer was "because i like to make mummy mad!". ah kids.

I think giving no attention to her (good or bad) when she does do it, and praising her when she goes to the toilet should be the right way to go. Ignore the bad behaviour, praise the good. I think maybe making Dh clean it up instead of yourself might be just ignoring the problem, and not really dealing with it. Maybe try cleaning her up with complete lack of any emotion at all. Dont even talk to her. I saw this on a child behaviour tv show the other week, and it worked a treat.

i hope this info helped. let us know how it goes. Good luck!!!