If you use Outlook.com as your web based Email program, it is possible to import an IMAP Email account from another provider and use Outlook.com to send Emails from this account.
After the initial import, Outlook.com does not read any further Emails from the external IMAP account, so you will have to set up a forwarding service to Outlook.com.
Please contact us if you require your Email account forwarded to Outlook.com.
Select Import email accounts
Select Other email provider
Now click on Advanced options
Enter the Email address which you wish to reply from. This might be firstname.lastname@example.org
and enter the login details for your Email account
Using your new account
Now when you create or reply to an Email, you are given a choice of which account to make the reply from.