Very strange ANTARES "Harmony Engine" issue

SONAR 8.5, Vista, 64-bit.

I am able to use "Harmony Engine" fine as an "audio effect" put directly on the vocal track and it generates its harmonies successfully via the "Default" or various other presets.

However, when I read up on sending midi to it and went back into Plugin Manager to reconfigure it as a VST synth, I can't get it to "stay" and appear in the list of synths.  I check the "Configure as synth" box and move it to the layout, it appears, I save the layout, I close the Plugin Manager window.  Rescan.  I then go back to my track to load this "synth" on my vocal track--and it's not in the list.  Sure enough when I go back to Plugin Manager...it's not there!!


I have successfully reconfigured various other effects as VST synths so that I could direct a midi track at them--I've never had this happen before.  Anyone know why it won't "take"?  (I've posted a similar question at Antares's forum, but no response yet.

Jerry