Gee, I forgot about that post. I just read through it again, and it is still accurate as-is.
Note that the very first thing I have on the bullet list is an assumption that your Google Voice service is already working correctly with your OBiTALK device. You must confirm that this works, without any added complexity of forwarding through Callcentric. It sounds like you didn't do that, or whatever you did isn't working. Go back and fix that.