I am using Microsoft Hosted Exchange Online Office365 service for our business email which manages 5 separate domains. 

Each Mailbox user has different (multiple) email addresses setup as Distribution Groups with SendAs permissions from their primary User Email Address.

Using Microsoft Outlook Web App, we can now choose the FROM address.

However in Outlook 2011 for Mac the FROM pop up is hidden.

Configuration settings for the exchange server points to a Microsoft server with auto discovery. There is nothing entered for the Directory Service.

How do we configure Outlook so that the FROM field is visible?