Hello !
So I’ve done this a while ago, but never updated it. It now goes both ways (input and output).
Just drop it in a midi track in Ableton, set the midi channel for input/output corresponding to the track you want to take control of.
It’s a very basic M4L patch, but it’s stable, I’ve used it in live situation a lot.
http://www.maxforlive.com/library/device/3582/octatrack-midi-ctrl
Have fun !