Is my step daughter beyond help???

Ive been married for 8 yrs and my husbands daughter is 15. Shes a juvenile delinquent (by the court) and she is a habitual liar. Shes seen COUNTLESS "professionals" in which she has pretty much told us they believe everything she says (manipulated) and shes gone as far as to accuse her father AND her step father of molesting her in which she rancanted months later, she comes to our house and talks bad about her mother and then goes to her mothers and talks bad about her father and I. We've tried everything (been in the juvy twice, counseling, ect ect) and we are at our wits end. When she gets mad at her dad, she dont come over, she dont talk to him and her mom believes every bad thing she says about us but the girls is just a liar when we tell her what the child had said about her..... anyway-- does anybody know what else we can possibly do???