I have tried installed several 3rd party plugins such as the Blue Cat Audio Frequency Analysis plugins directX version and they never show up CD Architect. Is there some special way you have to install them?
I found the problem in a FAQ file at Blue Cat Audio. You have to delete the dll cache registry key which caused CD Architect to rebuild the plugin cache. Then they show up. Here is a link for anyone who needs it: http://www.bluecataudio.com/Tutorials/Tutorial_DXiInSonyVegas/
I talks about SonyVegas but the same technique works fine with CD Artchitec.