Hi.
It's pretty simple to do so.
If you are using a Drum Rack, you need your pads to send MIDI notes and not MIDI CCs.
In a Drum Rack, each sample slot is triggered by one MIDI note.
If you are using the default USER mappings, the KeyLab MkII pads are set to send notes from C1 to D#2 on MIDI channel 10.
To use such mappings, please make sure you have pressed the USER button and loaded one of the 10 user preset.
Plus, make sure that in the selected user preset, the pads are sending MIDI notes and not CCs.
Then, in your Drum Rack, make sure to drop your samples on the correct MIDI notes slots.
Finally:
- Set your Drum Rack track to listen to the channel 10 only.
To do that, set it to MIDI From: KeyLAb MkII - Channel 10
- Set your other track to listen to any other channel than the Channel 10.
(Preferably the one used by the keyboard of your KeyLb MkII)
More info about Ableton Live MIDI In / Out:
https://www.ableton.com/en/manual/routing-and-i-o/Let me know if it helps !
Best regards