How to restrict permissions for administering Taxonomy? I would like a user role to be able to add/edit terms for a specific vocabulary, but not all vocabularies.

In the permission settings for taxonomy, it seems that I need to give the role permission to 'Administer vocabularies and terms'. But then they can edit all vocabularies; the edit/delete permissions for each vocabulary don't have any effect?

I've seen various taxonomy access modules, but they seem to restrict the use of terms on nodes etc. My situation is more simple; a specific role just needs to be able to add additional terms to a vocabulary.

What am I missing here?
For D7 there is a taxonomy access fix module. It makes it possible to manage access permissions to individual vocabularies.