Shipping is always
included in the taxation. Otherwise they may sell the shoes for 100$ plus 600$ shipping.
So the person who's willing to do it for you may end up being in trouble.
And FWIW, be happy that you don't live in Japan. Some guy in the Meermin thread said it's like 90% (IIRC) duty there.
What you can do is ask the shop to declare a different value on the duty form. If it's a reputable shop they're likely to not do it though. In that case, ask them to write down the wholesale price of the shoe. That is legal.