Have you used the PLUG IN MANAGER to ADD them to the list?
You need to go into the plugin mgr and add them to the list. I
d have to open Sonar/MC to give the details exactly...... but it's a simple process of adding them.... you add the location and name of the DLL file....
THEN.... you run the SCAN PLUG INS process.... it takes a few seconds to complete..... varies depending on the length of the list and the the computer's speed. Once that has completed, the new plugs and VST's should then appear in the appropriate midi or audio VST/Plugin lists.
I think the scan is set to run as a default on startup.... lots of folks shut it off since it's only needed to run when you add a new plug. Shutting it off shortens the loading time of the DAW.