Which regxpcom binary should be used to register components for firefox-3.0b*?

I have built, and am attempting to install, libnegotiateauth for firefox-3.0 on hardy.

I understand that xulrunner-1.9-dev should be used when building extensions targeting this browser version. However, unlike the libxul-dev it replaces, xulrunner-1.9-dev does not include a regxpcom binary. (xulrunner-1.9b3 includes regxpcom.py, but this throws "xpcom.Exception: 0x-7fffbffb (-2147467259)" when run).

How should I be registering this component?