Systems Saber III radio PIN?

[radio-link]

Hi,

in the RSS for the Systems Saber radios there can be found an item to enable a kind of lock code, to be able to lock the radio with a PIN. Enabling ist does not make a difference, and I can not find a way where this lock code could be entered. Any ideas out there? Would like to protect a bunch of SS III radios agains unauthorized use, like it could be done with the German public safety Saber III radios.