First make sure that in your PT plug-ins folder you have two files. one is the PS0X plug in and the alias form the dat file. If the dat file ends with alias word at the end then delete the alias part of it. Next go to pro tools mixer create an aux track - open plugsoudn as an insert - select the appropriate output which you use to monitor. Then create a midi track input use your keyboard output use your plugsound - I think you have to enable the record button to hear it live.