First...the squeal you hear is because of a vibration of the pad in the caliper. You hear this vibration as a squeal. Obviously, a smooth surface meeting a smooth surface minimizes vibration. Second, you never turn the rear rotors. Never. Third, turning the front rotors is also questionable. Fourth, there is a special shim that can be used on the rear pads, part number 272272, to minimize squeal. Fifth, I've learned to use Volvo pads only on the front, others can use what they wish, I have better luck with the Volvo pads. Sixth, turning rotors costs me $7.50 per rotor. Seventh, using the Volvo brake grease on the back of the pad also minimizes the occurence of brake squeal, and last but not least...

Your technician should have advised you of these facts. He knew that putting smooth pads on a grooved rotor was going to make one hell of a racket. He should have given you your options, and allowed you to make a decision. See if you can return the parts, purchase Brembo rotors, and Volvo front pads, and have him install them for you at labor cost. Or do it yourself, and take the parts back.

Chris