Thank you, I found it. By the way, LR4 seems to allow less manual corrections to the image. After updating a previously LR3 processed image, the menu is shortened removing some traditional tools like 'recovery', 'fill light' or, as I stetd in mey question, 'chromatic aberration' (in manual format). Although LR4 algorythms seem to work very well, I miss the old chance to process manually some image parameters...