Did you create a midi multi instrument on the environment page? I think you need to do that, and set the port to USB. Then on the arrange page, when you choose a midi track, there are some menu items in the parameters in the channel strip which allow you to choose that if its going to produce sound. Normally you would set the korg to be transmit midi and then use that for other synths and soft synths. I have one keyboard a number of modules and soft synths. Logic knows which module to sound because of what arrange track I am on.
