Internal messaging: main functionalities

The internal messaging system displays messages received from the Infrastructure or from other users on the interface of the user when s/he is logged in (it is NOT an e-mailing system).
It stores messages received from other users of from the Infrastructure in an "Inbox". It allows the user to send messages to other users using a "Write new message" function. It stores sent messages in an "Outbox". The function is very analogous to the "Privatemsg" module in Drupal (see the specification link to the description of this Drupal module).
The messages received from the Infrastructure are Authenticated Internal Messages.