Problem with deleting/editing comments (author-status)

Editing and deleting comments in WordPress version 2.02 is not possible for user with author-status
We use a WordPress weblog for internal use only in our library. Employees have the status of “author” and can write and publish comments in response to all posts. The problem, however, is that they cannot edit or delete their own comments once these are published. This seems weird, as authors do have rights to delete their own post but do not have rights to delete their own comment.
Is there a way of making this possible without changing their status to “editors”?