To make a shared mailbox functional in V10, it must be added as a separate account in Outlook.
A mailbox added as a separate account in Outlook under File/Account Settings/Email Accounts is a full MAPI profile entry.
V10 can recognise and send from these accounts.
Step 1 — Open Account Settings
In Outlook, go to File
Select Account Settings /Account Settings
Step 2 — Add the Shared Mailbox as an Account
Click New…
Enter the shared mailbox address (e.g., dailyorg@myschool.edu.au )
Enter the credentials
Outlook will add the mailbox as a secondary account
Step 3 — Restart Outlook
Once added, the shared mailbox becomes a full MAPI profile entry.
V10 will now recognise it and allow the user to select that address in the 'Send From' drop-down field in V10.