Passing "access_type = offline" to get refresh token for Google+?

Created by: ddellacosta

This is more of a help request, as I just don't know how to do it (sorry wasn't sure where to ask). Since this happened,

http://googlecode.blogspot.com/2011/10/upcoming-changes-to-oauth-20-endpoint.html

...I need to figure out how to get the refresh_token using the "access_type = offline" argument. But I just can't figure it out, probably because I don't understand the API/Oauth2 well enough. For example, I've put it in here:

::OAuth2::Client.new(GOOGLE_PLUS_ID, GOOGLE_PLUS_SECRET,
                                :site             => 'https://www.googleapis.com',
                                :authorize_url    => 'https://accounts.google.com/o/oauth2/auth',
                                :token_url        => 'https://accounts.google.com/o/oauth2/token',
                                :access_type      => 'offline'
                          )

...and I've tried it here too:

@access_token ||= client.auth_code.get_token(@code, :redirect_uri => redirect_url, :access_type => 'offline')

What am I missing here? I either get nothing in the refresh_token field, or I get an Oauth error.

Thanks!