dual monitors with ATI Radeon 9600
 

I'm running FC3 and have a ATI radeon 9600 graphics card and i'm trying to setup 2 monitors.
i go to the display dialog in 'System Settings' and check the dual head box and select the second monitor but when i hit OK it does nothing. the window stays open and nothing happens

anyone have any advice?
thanks

make sure first you connect the TV set or second monitor before boot and edit properly xorg.conf to enable it at X startup