I implemented this: http://android-developers.blogspot.fi/2013/01/verifying-back-end-calls-from-android.html and then wanted to make the app ask the full name of the user from google servers.
I can get the id_token all right, pass it to the backend, verify it and get the user id and email from the token, but I don’t seem to be able to find any way to turn the id_token to a token I could use to authenticate on google servers and request personal info from the profile scope. The google apps-app has the permissions to use the scopes, so as soon as I can understand how to get an auth-token, asking the info shouldn’t be a problem.
Is it at all possible to access the google servers with this token, or must I ask for a separate auth token for the personal info.
You should ask for a separate auth token for the personal info. The user has to explicitly grant permission for your app to see things like their name, gender, etc.