Hi Joost, (Sorry for my English)
I am very happy to know that you come back in down!!!!… RW town!
It's been a long time that I tested stacks (RWML) with 2-3 other people in the Forum, but from what I remember me,
I had difficulty understanding how to integrate the plugin "Sitemap" and SEO stuff for each language.
But if you wish, as here in Quebec we have to do sites in French and in English, I can make test again and make you
recommendations for a new update, especially since I work with RW now for 7 years, I gained a lot more expereince.
Let me know if you wish me to invest the time, I'd love to help you develop (set of stack) for those who need
producing sites in two or more languages.