Topic: how to setup authentication through google docs

I am new to GLPI and we are currently using it for a helpdesk system. We are moving to google docs and google mail. I used to have authentication going through our old email server but now that we are going to google docs for authentication I need to setup authentication using google apps or mail. anyone have a how to on this or any setting that they have tried and worked. I cannot get it to work at all.