By Fenrir.Mariane 2013-03-28 17:57:48
I don't know how it works with Windower as I don't use it, but to have the real JP version text input work you need to set the OS Non Unicode region as Japan (this causes a lot of programs to think the OS is Japanese Windows)...
Once that is set correctly the game will just let you use the bog standard Windows IME to write. (CTRL tilde key allow you to input hiragana on IME mode)
I don't know if it supports direct input and because I don't have a 106 key Japanese keyboard I cannot test.
Direct input requires the extra 5 keys to work.