Role Scoper 1.2.8.RC3 fixes a number of issues with custom type / custom taxonomy usage and role assignment. I have rushed to put this together before leaving for the weekend and have not had time to test it much.

After enabling your custom tx for role assignments (via Roles > Options > Realm), you will need to assign all non-administrators a corresponding Taxonomy Manager role to edit its terms.

Let me know of any continuing issues; this is only the first phase of RS revision to fully support the new WP type/taxonomy/capability definition schema.

The asterisk means you can't define role restrictions for that taxonomy because it is non-hierarchical tag-type (versus hierarchical category type). Role Scoper only applies restrictions if the taxonomy is required (i.e. at least one term must be selected for each supported post).