Drupal or OG role permissions for administering content?

I need to be able to let certain users post content on behalf of other users by changing the authoring information.

I know that the 'administer content' permission is retained by the Drupal permissions system, instead of being included in the OG role permissions system. However, it doesn't seem to be having the desired effect. The 'Administer group' permission in /admin/config/group/permissions/node/oa_space doesn't do the trick either.

I have created an additional OG role ('editor'), so would rather grant the permission to that OG role than make it site-wide.

Any ideas?