Notes and tips:
Ableton Live's MIDI preferences has options to enable "Sync" output and "Track" for each MIDI output.
The "Sync" setting activates sending MIDI clock which can be used to set the BPM of "Clock" plugin in VDMX.
The "Track" setting allows for sending notes, control and pitch-bend data from MIDI tracks. Each enabled 'Output' port in the preferences is available in the track 'MIDI To' menu.
Each track in Live can send out both MIDI notes and ctl (envelope) values at the same time.
Almost all interface items in VDMX can respond to MIDI messages from Live, including the Media Bin, sliders, buttons, and pop-up menus.
For more information about MIDI setup in VDMX see the introduction to MIDI tutorial.