Audition was completely rewritten for be cross platform compatible with Macs as well as PCs as Audition CS5.5. .cv2 plugins are therefore no longer compatible with any version later than Audition 3 which the SDK that you used was built for. So I'm afraid that it won't work.
In these later versions of Audition any controller plugin is kept in the ControlSurface folder within the Plug-Ins one in the Audition Program folder. All the new controller plugins are now in .acsrf format. So if you want to make your own controller software for CS6 you need to find a much newer SDK for Audition. Also controller plugins have nothing to do with any VST/VST3 plugins which are all for effects.
You won't see any of Audition's built in VST3 effects in the Plug In Manager since that is for managing third party plug-ins that you install separately. Usually they come as .dll files and are installed by default in somewhere like "C:/Program Files/Vstplugins".