I'm confused. . . the very first lines of your referenced "read" state: People who cannot contain their urges to harm (or kill) people repeatedly for no apparent reason are assumed to suffer from some mental illness. However, they may be more cruel than crazy, they may be choosing not to control their urges, they know right from wrong, they know exactly what they're doing, and they are definitely NOT insane. So why do you still consider her mental? See bold/underlined by me.
No amount of counseling will help her or anyone else with antisocial personality disorder. It would be entertainment to her. I lived with a guy with this (and other) disorders for 5 years. I finally pursuaded him to go for testing and he went because he firmly didn't think anything was wrong with him - should have seen his face when he was told! No amount of talking, trying to understand, stating the truth, shoving the truth in their face, absolutely nothing makes them tell the truth or change their ways. NOTHING.
Now, a better idea might be to study her to learn more about this disorder.
I would suggest anyone with a very young child, or will have one, learn as much as possible about these disorders because it appears that the first 3+ months of a childs life (how they are interacted with) can have very lasting effects. From what I've read, some genetics might be involved but there are alot of seemingly simple things (like eye contact & expressions, generally "connecting" with a child) that help shape us when we are this tiny. Just my opinions from my own experiences and efforts to understand someone like this. I wanted more than anything to find a way to make it work, finally gave up after too much emotional and finally physical abuse.