Peugeot Radio Problem?

Hi, I have bought one Peugeot 306 XT 1,4. It Came with a Clarion radio and stock front speakers. I Had a problem with my battery and the radio asked me for a code that is written in a paper of the owner's manual from the previous owner of the car. I went to my normal mecanic, and he fixed the problem.
A year later, I had the same problem, i switched the car's battery (it came with an Varta, i swithed to Tudor) and the radio asked for the code. I Used this site to find out that i must use the band button for re-inserting the code. (my mecanic closed due to lack of money and i don't know how to fix it) Now, i insert the code, and the radio doesn't respond. Can Anybody help me to find out what's the button to make the radio accept the code? Thanks.