A possibility but then "subscribe/unsubscribe" won't work and my mail provider might consider the mail sent from my mail program as spam.
I could try it, if I'd know the code. But I already know that this backfires and is still(!) extra work. So I guess for the meantime, I hope to get a PM with the HTML Newsletter script to check out on a test install, and use the phpbb.de script for changing the header/footer of the Mass Email (still in TXT form, but better personalization/legal imprint possible)