This is actually quite interesting. I might pick up her book. I've always been curious what the actual prospects are for getting involved in the manga industry in Japan as an outsider.
She is obviously not Japanese/Asian either, which puts all the more weight behind it.
It does seem that she lived in Japan for over 5 years before landing the assistant job though, so that semi-confirms what I assumed before: You need mostly fluent Japanese skills.
EDIT: Whoa, necro bump -- I swear I was on the first page when I saw this post. Very odd. Maybe I misclicked onto a very old page?