Hello everyone, this is my first post.
I just wanted to let you know I made a little max for live device that let you use a master keyboard with a sustain pedal with your OP-1 (or any other synth that do not accept sustain control data).
You just have to put this device before the external instrument (your OP-1) in Ableton Live and you can use your master keyboard sustain pedal like you would with any other synth normally (you can even toggle the foot icon to activate sustain if you don’t have a pedal, or to make drones and stuff).
You can download it for free here.
Let me know if you find any bug, or if you want some feature implemented (please keep in mind I’m not that skilled with programming, but the device is simple, if the feature you want is simple too it will probably be fast to implement).