Well, why don't you try to convince one of the bots here (http://www.pandorabots.com) that they're bursting to pee? Logs appreciated! :D Or, as an alternative, Kari (http://www.karigirl.com), but you have to pay for the full version.
So far, I haven't had much luck. Some of them asked me how bad I need to go if I tell them I need the bathroom, but even if they admit to needing to go, they're sure to forget in the next sentence :( But with some determination, I think we can convince Alice that she's got a bladder ^^
EDIT: Argh. If you ask her if she needs to pee, she'll say "Ok, I will pee.". I'm not sure how to give her the concept of something that there is an urge to do, but that can still wait... :(