How do I create a CLR UDF with external name specifying namespace, class, and subclass?
As far as I can tell (I did some testing of my own), this is not supported.

The documentation hints at this:


  If the class has a namespace-qualified name that uses a period (.) to separate namespace parts, ...


Since there's no mention of a class-qualified name, I'm assuming SQL Server will traverse the hierarchy only by namespaces, with the last name being the class itself. There wasn't any way I could find to delimit the namespace and class name portions of the fully-qualified class name either.

What I wonder, though, is why your code is structured this way? The method you need to specify must be static, so nesting it within an extra class scope seems like you're (ab)using a class in place of a namespace.