K.A.
I've seen and heard folks having rapid success changing entrenched habits using a harmless non-invasive intervention called EFT. You tap gently on a few acupunture meridians, and it quickly clears the pattern from the nervous system. It sounds sort of fringe, but even doctors and psychotherapists are teaching and using the technique with good results. Sometimes it only takes a few minutes of tapping to release the habit completely.
You can download the instructional manual for free at www.emofree.com.
Or you can learn it very quickly from Rebecca Marina's tutorial on YouTube. http://www.youtube.com/swf/l.swf?swf=http%3A//s.ytimg.com...
Might be fun to teach it to your daughter, and invite her to tap on a few points whenever she catches herself picking. Most kids love tapping, because it feels more powerful and fun than trying to use will power ...
Good luck!