B.G.
My friend had a son about that age who still wet the bed every night as well. She was told, and I agree, not to put a diaper on at night. No pull up, nothing. This way, he would actually feel himself getting wet and it would make him uncomfortable, making him get up and use the toilet in the middle of the night or wait until morning.
Would you consider letting her to go sleep with nothing on? Diapers are made so well nowadays (maybe too well) that children don't really feel when they are wetting themselves you know?