You can't register Blink for GV as an endpoint. You can use Blink to call a GV number via SIP (example here: http://truvoipbuzz.com/2011/03/make-unlimited-sip-calls-to-g... ) but you can't set up Blink as one of the numbers GV calls.

That's the missing piece I mentioned at the end of my article and has been made in several other comments.

Thank you for the clarification.

That's the crux of the article -- the sip in question is inbound sip -> gv # -> PSTN not sip client <-> gv <-> world

And at length, linked from the article: http://blog.duh.org/2011/03/so-google-voice-sip-is-actually-...