How do I deal with horrible people?

I have a shift leader that I really, really can't stand working with. She is volatile, aggressive, rude, and tactless. I have seen her be incredibly snarky and impatient with customers, and corporate has even had to intervene on occasion. I honestly don't know why the company has bothered to keep her around, because she would be easily replaced. Things got to the point that I requested to my store manager that I not be scheduled with her. He agreed that he would avoid it if at all possible, but did point out that there might be occasions where he has to schedule me with her.

Occasions such as this Saturday.

I am honestly dreading it. I haven't worked with her in a while, but I briefly interacted with her yesterday and it was pure rudeness spewing out of her mouth for the whole 10 seconds. I had done absolutely nothing wrong, but she just couldn't resist being a jerk. I am seriously stressing out about having to spend an entire night with her; I don't know if I'll be able to handle it without breaking down. Believe it or not, I'm kind of sensitive to hatefulness. I've talked to other employees about her, and not a single person likes her because of her attitude problem.

Any advice on how to deal with people like this? I've already tried being really sweet and kind, and it does absolutely nothing to her. (Might even make her even worse, actually.) I feel like I'm going to end up bursting into tears and going home early. I'm not a confrontational person so I'd never have the nerve to just ask her, "Seriously, what's your problem with me? Have I done something to you?" But I'm at the point that something's gotta give.