XML -> SGML serialization. Any ideas ?

Hello,


I have to give data to a very old application, which can only read SGML.

My data structure is really simple (records of filename, title), but 
contains characters that are not ASCII. So I have to translate them to 
use entities (I think SGML has a set of declared entities for characters 
with accents, as é, @agrave;, and so on).


I'd like the file could be read by XML parsers too, and I'm looking for 
a method to produce an XML that is also SGML. I think to use XSL with 
characters map, but how could I define the embeded DTD, with all 
entities defined ?

Any ideas ?


Best regards,
Christophe