Dotnetnuke: how to force dotnetnuke to send welcome e-mail as HTML not plain text

To force dotnetnuke to send welcome e-mail as HTML, you just have to modify MAIL_USER_REGISTRATION_PUBLIC_BODY.Text or EMAIL_USER_REGISTRATION_PRIVATE_BODY.Text strings in language editor. DNN Framework check if the mailbody contains html code and send e-mail in corresponding mode.