Mhh, I don't know.
I mean for the time being you can bake the black and white AO to the Base Color Channel and show only this channel, for export the AO image.
I know this are extra steps but currently I need to focus on a few other features.
Yeah I know you can do it this way it's just more steps. Hopefully you'll find time to do it though. UB Painter is a great tool.
