Antisocial Behavior of Arturia Oberheim SEM in 8.5.3 and work-around

My venerable and underpowered-by-today's-standards XP laptop DAW broke down, and I migrated my Sonar 8.5.3 setup to a new, i7 machine running Windows 7 Pro 64-bit, and did a 64-bit install.  My core tools all work fine on the platform, but I've run into a glitch with the Arturia Oberheim SEM emulation VSTi soft synth.  If I insert it into the project as a soft synth, it plays, but I cannot change patches from the GUI.  If, on the other hand, I do the Sonar 2-like approach of inserting the SEM in the FX box of an *audio* track, the UI is fully functional, and I can drive the synth from a MIDI track.  Does this ring a bell for anyone?  I can continue using the work-around, but if it's just some obscure plugin default setting, it would be nice to make things "just work".