Roles and permissions

Dear All,
I am finding it absolutely impossible to set up moodle so that any registered user can make a glossary entry. I have tried overriding the "registered user" role at the glossary so as to permit the addition of a new glossary entry but the "add" button still does not appear when a user is logged in. I have also tried enabling the "Add new entry" permission in the global roles to allow this but this also made no difference whatsoever. To be blunt, I am struggling somewhat to understand exactly how these roles work as they do not appear to be working as I was expecting them to.

Best regards,

James Phillips