[XeTeX] Chnese docs: traditional => simplified

[ahoenig at jjay.cuny.edu]

I successfully typeset  a Chinese/English document using (plain) xetex.993 and 
traditional Chinese characters.  I would like to 
typeset the same document again, this time replacing the traditional characters by their 
simplified counterparts.  In TeXShop, I 
opened the source, selected all of it, and converted from traditional to simplified using 
the 
TeXShop>Services>ChineseTextConversion tab.  As far as I can tell, this was properly 
done---I can see the simplified characters 
in the source.  However, after typesetting, all these simplified characters appear in the 
output as square boxes.  What am I doing 
wrong, and how can I fix it?  Thanks!!

---Alan