Hey dude,
I just received an J-Custom RG8527 from them yesturday. I live in New Zealand (we have lots of sheep).
The best ways to contact are below.
I initially went via email correspondance to "web-shop@ishibashi.co.jp"
You will probably get a reply from a chick called Noriko. Her english is ok/good and she usually deals with the International emails.
NOW, the BEST guy to talk to is "KOICHI". His full name is Mr Koichi Tanimoto.
Call this number +81-3-3291-7090 and ask for him. He has very good english and sounds like he was trained to speak with an American accent (if it helps

)
He basically is there to answer International quieries (along with Noriko) and knows his shizz.
I have spoken to Noriko on the phone but her english isnt the best over the phone (better in emails).
Both Noriko and Koichi can be reach on that phone number above.
This website explains some things.
http://www.ishibashi-music.com/
Lastly, the best advice I can give ya is have ALL your question ready BEFORE you call 'em. Everything about fees, duty, customs, insurance.....etc. Oh yeah, make sure that the in-house tech sets up/test/inspects your guitar before they ship it. If there are any problems they will let you know.