DOS 2.1 introduced the use of code pages (see
http://en.wikipedia.org/wiki/Code_page ).
Implemented via a COUNTRY command in CONFIG.SYS
I have never had to use it.
Some of the references on the Internet suggest that it changes DOS' character set (as well as other things).
Perhaps that may help.
Perhaps you are already aware of code pages.
COUNTRY
========
Enables MS-DOS to use country-specific conventions for displaying times,
dates, and currency; for determining the order by which characters are
sorted; and for determining which characters can be used in filenames. You
can use this command only in your Config.sys file.
The COUNTRY command configures MS-DOS to recognize the character set and
punctuation conventions observed when using one of the supported languages.
Syntax
COUNTRY=xxx[,[yyy][,[drive:][path]filename]]
Parameters
xxx
Specifies the country code.
yyy
Specifies the character set for the country.
[drive:][path]filename
Specifies the location and name of the file containing country information.