Saab 9-3 ( Yr 2000) Front Rotors

HI. I cannot seem to get the front rotors off. They seem to be siezed onto the wheel hub. I took off the calipers and backed out that little hex screw on the face of the rotor. Am I missing something, or is it just a case of using PB Blaster spray and a big hammer? Any help I appreciate!

Thanks