Nothing 'fail' about this. They have said from the start "do not expect to be able to customize C3D in lisp, not everything is, or will be, exposed for use in lisp". Those who choose to try to do so are basically doing so at their own risk. I gave up trying to force it to work in lisp 7+ years ago. I still can't do EVERYTHING I'd like to do with the API's provided, but I'm pleased that I'm at least able to do a LOT of what I want. Unlike some other civil packages out there.
And, fwiw, C3D development is still alive and kicking.