Why is Kato in the Green Hornet movie foreign?

I'd like to know why a foreign Asian actor was chosen for Kato when there are enough Asian American actors like Will Yun Lee and Daniel Henney. I don't mind stereotypes as long as it's not overdone, but judging from the preview, why did the filmmakers choose a foreign asian actor that speaks with an Asian accent? What's wrong with an Asian American actor like Will Yun Lee, he's a marital artist besides an actor and he is well known, plus he doesn't speak with an stereotypical Asian accent. Bruce Lee didn't speak with an Asian accent as Kato. Again, I'm not trying to prejudge the movie (because I rather see stereotypes than not at all), I am just saying, there are enough Asian American actors who are capable of taking on the role as Kato. I'm gonna see this movie regardless.