ford ka cd player m000456 - locked?

Hi there, I´ve got a CD player in Ford Ka 2002 unit type FD600A, Ser. number M000456 and key code 1211. Display says LOCKED and there is "3" below that sign. I have tried everything but I can´t make it to work. Has anyone would have any idea or is there any procedure how to encode the radio? I tried to hold 3 and 6 and the radio started to play but only about 10sec. I looked like it tested speakers (right, left and both) and the only thing I could do was turning up and down the radion. Thanks for any idea.
Michael