[Building Sakai] Google drive LTI integration

[Ciellie]

Hallo

We are very interested in the google drive LTI integration with Sakai. We
want to test it as a way to sync content offline by using it with the google
drive app.

I tried to install it on a dev box with Sakai 2.9.3 

1) First I created a service account enabling the Google Drive API and
Google Drive SDK. I did receive a .p12 file and follow the instructions on
https://source.sakaiproject.org/contrib/umich/google/google-drive-lti/trunk
/README.TXT

2) I checked out the sakai 2.9.3 source build and deployed it
3) I checked out
https://source.sakaiproject.org/contrib/umich/google/google-drive-lti/trunk
build and deploy it
4) Copied the google-drive-lti to tomcat/webapps directory
5) Set the Google service account properties as described in the README.TXT 
6) Start tomcat
I use tomcat on Mac OS Lion
All went well but I can't get a access token

Sep 12, 2013 11:11:09 AM edu.umich.its.lti.google.GoogleLtiServlet logError
WARNING: Error: unable to get access token.

Thank you for the help
Ciellie