Authentication

I am using the SAML authentication plugin ( https://moodle.org/plugins/pluginversions.php?plugin=auth_saml ) with CMS being the IDP. But there are some questions, as the plugin doesn't seem to function as wished: 

1. Why I cannot logout from Moodle, when logged in through SSO? (I log in the CMS and then go to Moodle)
2. When using the CMS as IDP I cannot log in as an admin. Is there a possibility to use a backdoor (something like in the saml2 plugin)?
   
3. Does SAML allows us to get the custom fields from the CMS to Moodle through SimpleSAMLphp?

Every feedback would be appreciated. 

Thanks, 

S.