You have to build a single CJK truetype font on your own, because you can’t link fonts continuously on Windows CE as you have done with Windows XP. You might try versions of CJK truetype fonts such as CyberCJK, Code2000 or MS Arial Unicode. Link any CJK font you choose to the default Tahoma font.
!!! efont.ttf is a bitmap only font, so vector-oriented display schemes like Picsel browser can’t render its glyphs.
This is, actually, a custom-built truetype font based on the XCJK project, only for personal use currently, though. It weighs about 13MB. 🙁
The first picture above is showing how to type Chinese characters using CE-Star. Of course, you are also able to input Korean and Japanese as usual using Diopen, MS-IME or ATOK at the same document.
Here are some CJK examples on sigmarion 3.