To create a new mailbox login to the MSPControl and click on Mailboxes,
or go to Organizations > Exchange > Mailboxes.
Click New Mailbox.
First, check the radio button Existing user.
First, select the user from the drop-down menu or start typing his display name for quick search.
Then select the Mailboxplan (mandatory) and Retention Policy (optional).
If you thick Send Setup Instructions, instructions will be sent to the specified email address.
Finally, click Create Mailbox.
Hooray! The new Mailbox has been created, and you have been redirected to a Settings page for this Mailbox.