MIDI mapping with Rekordbox and FLX10

Hi

Looking for a solution to re-map "Sampler vol" knob at FLX10 to Rekordbox "PARAM" in Color FX section.

I know where are MIDI mapping at Rekordbox. But when I trying to do that, I got the message about it cannot be done just because.

Any tutorial? Any idea how to? Anybody?

I saw this topic -> https://www.reddit.com/r/PioneerDJ/comments/1262m0i/mapping_flx10_sampler_volume_knob_to_color_fx/ but after done it, it still not working. After import the CSV to MIDI at Rekordbox, its imported but it doesn't work at all.