I\'m using R3A X-Panel Mgr and I think it don\'t work on X2 Panel Manager.
First, Just Press X-Panel Button
Second, Execute setting
Third, Press the Radio Panel and you can see 2 button icon.
You just need to select the \'configuration\' button. Over there, you can see the appropriate Japan frequency Radio.
It works when I went to Okinawa last week. FYI, mine X1i with all original ROM, Panel Manager and of course panel Radio is still original.
But still no good for me as I can\'t speak Japanese.
Good luck,