Edit common name and Exchange mail address:

Choose POP as server type, located at localhost:

Populate in and out login names with Active Directory account name, i.e. domain\account

Edit account name (email address by default):

Finish:

Create a new outgoing mail configuration under account settings:

Server name is localhost, edit port according to DavMail settings. The connection must use authentication with Active Directory account and encryption is not needed.

Proceeed to Thunderbird calendar setup