Back -- Payment method?

Hi guys,

I'm taking music lessons and need to buy sheet music
from (an online site that makes sheet music
for many recent j-pop songs).

My problem is that my American credit card doesn't work.
I think the banking system in Japan is different and they
only work with Japanese credit cards.

The other payments options include:

Webmoney (not to be confused with another company of the same name)
NTT Docomo keitai
auかんたん決済 (KDDI)

I'm pretty sure the first 3 are virtual e-money methods that are popular in Japan.
NTT and au are cellphone payment methods.
I'm not sure about the last one (which is from Rakuten, a popular net e-tailer in Japan)

I don't mind signing up for Japanese e-money, but if my credit
card doesn't work, there's no way I'll be able to load any money.

So does anyone have any suggestions for how I
can pay for things at

Edited: 2011-03-03, 8:28 pm
sorry for the horrible thread necromancing, but i stumbled upon this question here by chance and it seems google doesn't readily give the answer, so i'll answer the question here, hoping it will help of help to someone in the future.

It's been a while since i did, but back then i used the rakuten payment option. With it you pay through your rakuten account, and in contrary to most other japanese online shops, rakuten actually accepts non-japanese credit cards. Remember, that was several years ago, but i doubt that has changed. So if anyone outside of Japan wants to buy something from, try the rakuten payment option (楽天ID決済).