Hey first of all I love this plugin, it was exactly what I was looking for and luckly I found it after a not too long of a search.
I got a question/problem tho.
I got 3 domains setup domain.com, product.domain.com, artikel.domain.com
now product. and artikel. work fine and so does domain.com
But somehow this plugin messes your http://www.domain.com redirect to domain.com up
when I go to domain.com all is fine but when I got to http://www.domain.com i get this
Fatal error: Out of memory (allocated 279969792) (tried to allocate 39 bytes) in /home/admin/domains/domain.com/public_html/wp-includes/functions.php on line 2331
Now I could probly make a http://www.domain.com setup in minimu but this cant be good for seo, seems like your than basicly creating to different sites with the same content