Sorry, but Google Voice's call screening function is not supported when calls are forwarded to an OBi via the Google Chat protocol. If this is something vital to you, then you would instead need to forward the inbound GV call to a real, 10-digit US telephone number, and provision that number on your OBi. Many of us use a free NY State phone number from Callcentric as the forwarding target instead of Chat. You'll also get caller ID name (CNAM) when known to the CNAM provider.