Inside tire wear

What is your question?

I get about 12000 miles on new tires on my CLK 430 Mercedes. The tires wear out on the inside,I get about 12000 miles out of a new set of tires, the tires are 245 I took and had four wheel alignment but the alignment guy said the car had a negative 2 degrees camber on the right rear and 1.5 negative camber on the left rear the problem is there is no adjustment on the rear wheels. Is there a kit or something I can do to improve the tire wear.