1st lets verify your AD LDAP settings are correct.
Goto Settings => LDAP Server Connections => and "Test" your AD settings. If you select "User Group" and "Test" with out entering any group information, do you get a list of AD groups? (Enterprise Admins, Domain Admins, Domain Users, etc).
Now when you create a new policy manually, you can use the scope option to "Limit this Policy to the following Users" and type in a Group name.
Example: http://cl.rummel.co/image/37312i1H2F0f
Thank you for your answer!
My post slipped into the wrong category, it should have been published under the 'Beta Discussion', sorry!
In Version 8.7 everything works fine with the AD connection!