From all we know it's not possible to register for the newsletter with the same account if you missed out on it when you registered. But I found out that you can register again with the same email address although the systems tells you it's not possible.
Fill in the sign up form once more just using a different username and password (and don't forget to check HTML this time

). After clicking 'Register' you will get an error message indicating that your email address already exists in the database. When you look at the forum index page you should however find yourself as the newest member. Check your emails then for the Request for confirmation where you have to click the confirmation link. This worked for me, so I dare to hope that it'll work for you too!
Good luck,
Gabriele