Hi Julien,
Firstly, I cannot see anything about sending it internationally. So the following, I am guessing, only applies to Japan. However, you could still try and see how they respond.
The transation is as follows;
Please send your name, your name in furigana (Japanese phonetic alphabet - perhaps not necessary), postal address, phone number, e-mail and the number of CDs to be ordered. There is also some note about sending another name if it's different from the person ordering (sorry, it's really small and hard to read and I cannot increase the font size). I guess if you're the person ordering, paying and receiving the CD/s you can ignore this. Send all of this to the e-mail you see on the site.
They will then send you a confirmation e-mail. If you don't get an e-mail within 3 days send another one to them to enquire about the progress.
Payment is by bank transfer and the price is 2,100 yen (for one CD) plus postage (200 yen). For 1-2 CDs the postage is 200 yen, for 3-4 it is 360 yen and for 5-6 it is 520 yen.
I recommend you keep your correspondence in simple English in case there is no one this end (Japan) who has good English ability.
Good luck!
