Official comment
@Giorgio > Sorry, that could be an issue with the pad-one sending MIDI signals that rekordbox isn't listening for - for example, if rekordbox expects a pad to register a value of 127 in order for it to trigger, and your pad-one is sending anything LESS than a full 127, it won't trigger.
Consider using a MIDI monitor to dig into the signals your pad-one is sending, and consider using a remapper if necessary.
Unfortunately there are no non-encoder methods for browsing tracks. You might also look at a MIDI-to-keyboard converter to send a key stroke signal from your MIDI input.