How do I setup shared Exchange mailbox with Mail (Yosemite)?

Question

Hello,
we use Office 365 hosting for our mails. Setting up my default Exchange account is no problem at all, just provide e-Mail address, password and let auto discover finish the rest through System Preferences -> Internet accounts.
But I also need to setup two shared Exchange mailboxes. If I setup the e-mail address of the shared mailbox. I tried to set it up as follows:
System Preferences -> Internet Accounts -> Add Exchange Account
Name: Shared Mailbox
Email Address: [email protected]
Password <own AD password>
As expected: Internet Accounts couldn't log in to the Exchange server "autodiscover-s.outlook.com". Make sure the email address and password you entered are correct. Then, enter your user name and click Continue.
<Continue>
Account Settings
Account Type: Exchange
Description: Shared Mailbox
User Name: <own smtp mail address>
Password: <own AD password>
Server Address: outlook.office365.com
<Continue>
Account Summary
Account type: Exchange
Full name: Shared Mailbox
Email address: [email protected]
Server address: outlook.office365.com
<Continue>
Select the apps to use with "[email protected]": Mail
=> There was a problem setting up the Mail account: an unknown error occurred.
05/01/15 13:02:10,706 com.apple.internetaccounts[313]: Already have account E2E3FF00-2B0E-4F75-ADD9-FB********** configured for user: <[email protected]> host: outlook.office365.com
So to add an additional account to access a different mailbox on the Exchange sever with the same credentials as the personal mailbox is apparently no option any more. On the other hand I haven't found any option to add according folders from other mail address inboxes to my personal account in any of the Preferences from Mail (Yosemite, 8.1) or any menu item, that would allow me to add the inboxes of other shared Exchange server mail boxes I have access to.
The same is true for Mail (iOS 8.1.2), thus I have not found a solution to configure the shared mailboxes on my iOS devices either.
Trying to setup an "Add Other Account" using IMAP did not succeed either. It always uses my personal mailbox, because I only have my personal user to access the shared mailbox and downloads my personal inbox instead of the one of the shared mailbox.
Do I really have to fall back to Outlook 2011 Mac to be able to use this feature and miss out on all the hands off features from Yosemite?

Answer 1

i too use office 365 shared mailboxes  and it took me a long time to work out to add them to my ios mail app , this worked for me :
start setting up a normal exchange account , put your shared email address in the username and you main email account password.
it will fail to do the auto-discover thing , but when you click on continue it eil allow you to manually enter the details :
Name : < whatever>
email : <your shared email a/c address  i.e [email protected] >
description : <whatever>
incoming mail
Host name : outlook.office365.com
username : <your main email address / shared i.e  [email protected]/myshared >
password : < your main account password >
outgoing mail server:
SMTP : smtp.office365.com
username : <your mail email i.e. [email protected] >
password < your main account password >
use ssl  <YES>
authentication : Password
server port 587
this worked fine on every IOS device i own, but somehow it doesn't work with my Yosemite mail   , so if anybody can help with Yosemite mail it would be much appreciated.
Cheers;
RP