My car has got ABS and Ive bought some black diamond discs for the back.These discs have come without a sensor ring sprocket on the back and we cant get it off the old discs as its all one piece. Renault dont do them at all. So how in the hell do I get these discs to fit properly???????? does any1 know where and if I can buy these sensor rings for press on the new discs?? (L-reg 16v) URGENT!!!! Thanks.