how do i get my Vitiras R8 into programming mode?

Hi can anybody assist we had a power failure and my system went into battery backup which totally drained the battery. I have fitted a new one but the system wouldn't set all the PIR's were lighting up as if zones were open, in the end i put the system back to it's factory settings. I can set the system using the factory code 4321 but it won't let me go into the program mode to change the codes ?? anyone help