I do not get a message automatically, asking to add any new e-mail address to the SendAccount List.

You will not get a message if SendAccount is configured to NOT display a message to add e-mail address to SendAccount list. To configure SendAccount to display this message:

1.Go to Inbox - Addins4Outlook menu - SendAccount menu.
2.Click Options. The SendAccount Options screen will open.
3.Place a tick in "Show message asking to add e-mail address to SendAccount list".