Hi Scott,
That would be a great thing if that would work.
Unfortunately, I have such a player does not then I could help you.
You must for some buttons usually two commands entered example. Search button once for up and one for down. (At least that's when Serato)
Have you already read the following instructions by?
https://rekordbox.com/_app/files/img/MIDI_LEARN_operation_guide_en.pdf