Roles and permissions

We are using version 1.6. We would like to define our non-editing teacher role to not be able to manage grades, grade manually, or delete quiz attempts (these are in fact our student advisers).

When defining the role through the site admin area, the changes seem to stick. However, when I log in as a non-editing teacher, I am still able to delete quiz attempts through the Results area in the grades section.

Do I also need to define this role somewhere else?

Please advise!

Thanks!