I succeeded to fully connect my Arturia Keylab MK2 88 to Cubase.
first I had to select the “CUBASE DAW mode” on the keyboard.
Then on Cubase I kept only Mackie Control (it work also with Mackie HUI).
But, very important :
I had to connect MIDI-in to MIDIIN2 (keylab mkII 88) and out to MIDIOUT2 !!!
Do nout use the primary "Kaylab mkII 88 "!
WM.