Documenting methods for which there is no source

I started work on documenting RSS. However, all of the normal methods 
you'd use to traverse the parsed RSS object hierarchy seem to be 
implemented via reflection. Hence, there's no actual code to stick 
comments around to get Rdoc to document the methods.
Is there a way to deal with this kind of situation using Rdoc? If not, I 
guess I'll submit what I have so far, as it's better than nothing...
mathew