DOCBOOK: Generate Chinese PDF file

I am wondering if there is somebody who did generate Chinese PDF file with
docbook xslt stylesheet. There is no problem with English docbook
documents. But all the Chinese characters were rendered with
un-recognizable characters when applying the same mechanism to produce the
English ones.

Working environment:
===================
Linux box with RedHat 7.1
IBM Java 2 Run Time
Apache FOP + DocBook XSLT 1.46 experimental stylesheets

command: $JAVA_HOME/java -cp $LIB_HOME/xerces.jar:$LIB_HOME/xalan.jar:$
LIB_HOME/fop.jar:$LIB_HOME/jimi.jar org.apache.fop.apps.Fop -xml my.xml
-xsl docbook-xsl/fo/docbook.xsl -pdf my.pdf

Any helps are much appreciated

Sidney Lu
Academia Sinica Computing Centre
Taipei, Taiwan