sometimes bedwetting is caused by an imbalance in the child or a particular hormone not working the way it should-it happens a lot in children and can be fixed with a nasal spray-perhaps you should take her to the doctor and discuss this. there could be a very simple solution!
good luck!

have you tried letting her have a friend sleep over and tell her before hand that her friend wont expect her to be wearing a nappy or to wet the bed and might think shes a baby for doing so.