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?
Reference:  http://community.office365.com/en-us/forums/160/p/71382/266109.aspx#266109

Using Office365, one of my users has mac outlook 2011, windows outlook 2010, and obviously OWA.

She has a distribution group where she's the only member, and she has SendAs privilege (I assigned via powershell). In outlook 2010 and OWA, she specifies the From, selects the distribution list from GAL, and sends. From that point onward, it always appears in the From drop-down.

On Mac Outlook 2011, the From drop-down only lets her specify another account on her computer; doesn't seem to know about any SendAs permission, doesn't seem to give her the ability to SendAs another email address from the GAL.

Is there something we're missing? Or is it just not supported?

We tried waiting a few days, deleting and recreating the account from Mac Outlook 2011, waiting a few more days... Still nothing.