would love if i could trigger a clip in millumin by playing a clip in ableton. that would be perfect for the live show i am about to prepare.

Not sure what ideas you already have planned for this and I'd bet we're all interested to hear them. You indicate that you are implementing MIDI, and while ableton has extensive MIDI, if this is done correctly, then it should match up easily.
One thing that bugs me about using ableton for av set-ups, is that what I always really want to do is to trigger a clip in Ableton, and have it linked to a specific video loop in whatever vj software I'm using - however, in Ableton there are no MIDI messages sent out from the clips themselves, which requires the creation of a sister MIDI clip to send the messages. But I doubt this is something that can be tackled by anyone except the Ableton programmers themselves.