Hm... All I can really think of is that, in the US, nothing that is Japanese is usually accepted by anybody other than anime nerds, not just because it's foreign and they don't like that, but 'cause, you know, the Pearl Harbour thing. :\ And uh... Well, the thing about Japanese music is, it's still fairly isolated, just like the country. Really the only countries that both are completely open-minded about Japanese music and that the Japanese try to share their music with are other Asian countries.
I guess, in parts of Europe certain Japanese acts are almost like underground stuff, and it's had at least some success. (Like, I have a friend who moved to Greece, and she says there are several "J-Pop/Rock festival" thingies all year. And an Internet pal I have from Hungary says she knows a surprising amount of people who like J-Pop.) But other than that...
(Sorry, I'm not much help. XD)
Maybe you could try to build something off of where Japanese music has had success because of similar styles? Like, I think it's had some success in parts of Europe because both they and the Japanese like to use heavy synthesis stuff. (Eurobeat?
) And how it can make it in other Asian countries because of related cultures.