HUH ??? I agree with Jack. How can a straight, non independant rear axle be anything but straight? Something is missing in this story.

If this is true, you have bigger problems than your disc brakes. Give us more info.

Is it a stock, non narrowed axle? How have you determined the camber is negative? What do you mean it is causing problems with the discs?

Be really specific, because this is weird.