Just thought I'd post a note in case anyone else falls for this.
I could not change the product info in my builds... it would appear to me that Cubase 4 copies the vender and version info internally and only updates it if it sees a new DLL with a new date... ie keeping the interop (xxxx.dll) the same and doing rebuilds on
my plugin xxxx.net.dll made no changes to vendor and version show in Cubase even though it functionally would change.
I've now changed my build events on my project to do a "Touch" on the xxxx.dll interop file in the cubase VST directory - solved.
Anyway ... whilst here ... briliant work obiwanjacobi ... now to see what I can do with it.