Is there any "proper" way to administer mailboxes, when you do not have the E-mail & Conferences module? Mailboxes are available in Technics > Settings, but you can only see the mailboxes in here, you cannot go into the properties of the mailbox to close or delete it.

I have a clumsy workaround, which is to create a new concurrent user, create a mailbox, and from the mailbox window, press F3 to display the list of mailboxes. From here, you can open any mailbox and close or delete it. Then, you need to delete the concurrent user you created.