I always ask them if they will accept an IPMO!  I 
explain to them how it works and that there is no 
fee required to convert it to yen at their post 
office.  With this explaination, they usually 
will go for it.  Doing a bank transfer costs 
money and takes some time.  

The safest route for you is to FIRST ask if they 
will ship internationally.  If they say YES, then 
ask if they will accept an IPMO. Only AFTER they 
say YES, then go ahead and bid.  Don't bid until 
you've cleared up the matter of how the payment 
is going to be sent.  You'll end up screwing 
yourself if they won't take the IPMO and insist 
on another form of payment.  Hope this helps!