Sonar will not see Pianteq as a plugin

Greetings all, new user as of today. I'm running an older machine with W2k (I know, not supported, but I've had much better than average luck running several other apps in the same category) and both Sonar 3PE and 6PE. P4 chip at 1.5GHz, playback on standalone is flawless with buffers set at 256mS. Interface/soundcard is RME Multiface with ASIO drivers. I've tried several times to scan for the plugin file, but it never shows up in the list within Sonar. I'm sure of which plugin folder it resides in, still no luck. I can use Pianoteq as a standalone routed through my console and back into Sonar, but then I lose ability to alter parameters once a track is recorded, ie: mic placements etc...since the recording is audio and there is no presence of Pianoteq within the host. Any suggestions greatly appreciated!