These newsletters have always been hard to create as regular web HTML is not properly read by web email interfaces and email clients. I thought that the simplest solution would be to use a web page that would serve as a web version of the newsletter and turn it somehow into newsletter HTML.
To fix issues with display of special language characters once and for all
there's a solution: use Unicode UTF-8 everywhere. If everything is set up to use Unicode, you can use mostly every language in your application.