I tried what you tried in my app. It seems that the google servers _DO_ respond with a meaningful answer, however this is what I get: Code: {"app_version":6,"x_failure":true,"auth_failure":true} What you've found is definitely a very big step in the right direction but we need more! See this line onwards for what I've done.
{"app_version":6,"x_failure":true,"auth_failure":true}
{"gvx":"random-letters-and-numbers-here:thirteennumbershere"}