can't get yast2 control center as root

well I decided to use blackbox and now I can't get yast2 control center to run as root. I can get it from the menu but its just user mode, if I type in su it won't let me open it and gives me this error: Xlib: connection to ":0.0" refused by server Xlib: Client is not authorized to connect to Server y2controlcenter: cannot connect to X server :0.0 How to I fix this?