jit.cellblock font question

Hi,

How can I set font of jit.cellblock by message and/or script ?

I found jit.cellblock can display Japanese characters correctly by
using 'set' + Shift-JIS codes.
It's very useful because it could avoid the escape characters that
break Japanese text.
But Mac and Windows have different system fonts and I hope to change
the font of jit.cellblock dynamically.

In addition:
I know a font-mapping but there's no default definition of Japanese
fonts.
I added Japanese font-mapping definition to max-fontmappings.txt.
It works fine with comment and other objects but jit.cellblock seems
NOT to be mapped.

Thanks for help.

Masayuki Akamatsu