In this case, a "wrapper" is software that will make an app such as CD Architect run VST plug-ins, although CDA is designed to run only DirectX plug-ins.
I use the Cakewalk VST Adapter, which works fine for me in CDA under Win7. I am not sure whether Cakewalk is still selling it -- or if it will work with Waves plugs. But the page is still there:
Good suggestion, Weka. I have almost all versions from Pro Audio 4 through SONAR X and couldn't remember how everything worked after Cakewalk bought the wrapper from Kirill. At some point, it became an integral part of the SONAR product, I think.
Can the bundled wrapper be installed without installing S 3 or 4? If so, I wasted money buying it separately. Oh well.
Just a note: If you use the Sonar 4 wrapper and it fails to work as expected under Win 7, go to the Cakewalk site and hunt for the update plug. I've just moved to 64 bit and have the wrapper working fine (unexpectedly).