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.