Create a new file in Notepad++ and make sure the encoding is UTF-8.
Type in the characters you want as a from address.
Select the characters you would like as a from address, go to
Plugins > MIME Tools > Base64 Encode.
Insert your base64 encoded text between
=?UTF-8?B? and ?= <firstname.lastname@example.org>
The complete text in mailing options.
Characters and resulting string.
Translation: My hovercraft is full of eels
Alternative method to achieve the same result.