I spent a bit of time figuring out how to install a Japanese font on the O2 Xphone II. Thanks to an excellent forum thread on ppcsg.com I was able to get it all working pretty quickly.

I found a nice list of Japanese Unicode Fonts here. I'm using EPSON 太角ゴシック体Ｂ (epkgobld.ttf) from the I Love EPSON website - it looks reasonable, but best of all is only around 2Mb.

If anyone else wants to try it out, here's the INF for the CAB file I use to install and uninstall the font as necessary. Just build with cabwizsp.exe from the Smartphone 2003 SDK.

IMPORTANT: As per the forum thread linked above, because the registry changes modify the default font path it is necessary to copy some system fonts (I copied nina.ttf and ninab.ttf) from \Windows to \Storage\Windows\Fonts. If this is not done the device will not boot, and will require a hard reset. (I haven't confirmed this, but I'm not ready to risk it just yet).

[Version]
Signature="$Windows NT$"
Provider = "DS"
CESignature="$Windows CE$"

[CEStrings]
AppName = "EPSON 太角ゴシック体Ｂ"

[CEDevice.ARM720]
ProcessorType=0

[DefaultInstall]
AddReg = RegSettings.All
CopyFiles = Files.All

[SourceDisksNames]
1 = ,"Managed",,

[SourceDisksFiles]
epkgobld.ttf = 1

[Files.All]
"epkgobld.ttf",epkgobld.ttf,,0x20000001

[DestinationDirs]
Files.All = 0,"\Storage\windows\fonts"

[RegSettings.All]
HKLM,Software\Microsoft\FontPath,FontPath,0x00000000,"\Storage\windows\Fonts"
HKLM,Software\Microsoft\FontLink\SystemLink,nina,0x00000000,"\Storage\windows\Fonts\epkgobld.ttf
	,EPSON 太角ゴシック体Ｂ"

Unfortunately I haven't worked out how (or if it is even possible) to enable support for encodings other than Unicode.