Only one instance of VST

[Smokey5159]

Hi all,
I am very new here and was hoping that someone could share some pointers about inserting Legacy soft synths. I have currently got Sonar 8.5, and was very keen to try using it with Korg's Legacy synth package (M1, Wavestation etc..) as a soft synth - it currently works as a stand-alone with a midi keyboard connected. I can access it as an insert whilst in Sonar, but if I select anymore than one track (instance) in a particular midi track, then I get no sound at all - although I can see the sound meters moving.
If I only choose 1 track with say M1, and the others Roland synth, then I get audible output.
Has anyone any ideas as to what my problem is..?
Thanks - Paul.