For those who want to stay with the original frameworks coming with the Oxygen 1.0.2. themed ROM or with the AOSP classic ROM, I created this ZIP to apply my Softbank Japan mods without flashing a whole ROM.
iWNN IME (Japanese keyboard)
APN for Softbank flat rate
Special version of Phonecard Express to handle international numbers
You can download this mod from my download page and flash in recovery.
Or you can get the mod from the Oxygen Updater. Start the updater on your phone, goto Themes screen, and search for “Mod – Oxygen – Softbank Japan 1.0.2.m”. If you cannot find it, update your list of featured theme servers.
Giving it a second thought, this might work as well for other ROMs, not only for the Oxygen ROM. But I did not test it.