Key mismatch when running Windows 7 (Japanese ver) on MBP (English ver

Hello. I installed the Japanese version of Windows 7 Professional 64-bit on my MBP i7 2010. My computer has an English keyboard. I found that some of the keys are mismatch. For example, typing shift+9 displays ) rather than (. Typing shift+" displays *. Could anybody please let me know how to fix this problem? Thanks.