John,
sorry it took so long to get back to you. I have tried Spat in both stereo and 5.1 mixes. Obviously, there is some setting in Sonar that I must not understand. Every other plug in I have works, very easily, but this one will only allow me input and not any output.
Also - the Cakewalk support people told me that Spat cannot be used as a multi-channel plugin like it can in protools. I can accept that, if only i can get SPAT to work in one channel, for one track. Even that would make me excited beyond belief.