non English in HtmlHelp

I'd like prepare HtmlHelp using DocBook under cygwin.
This is my first try with DocBook and cygwin.
It is OK if I use English. I need non English and then I have some problems.
I found solutions in documentation of DocBook and mail list, but that does
not help me.
Hho could find error of my solution?

My main XML file is:

<?xml version="1.0"?>
<!DOCTYPE set PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
                    "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
[
        <!ENTITY chap1 SYSTEM "chap1.xml">
        <!ENTITY chap2 SYSTEM "chap2.xml">
        <!ENTITY book2 SYSTEM "book2.xml">
        <!ENTITY faqs SYSTEM "faqs.xml">
]>
<set><title>To jest tytuł obu książek</title>
</set>





My main XSL file, where default htmlhelp XSL file is called, is:


<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    version="1.0">

<xsl:import href="htmlhelp.xsl"/>

<xsl:output method="html" version="1.0" encoding="'windows-1250'"
omit-xml-declaration="no"/>
<xsl:param name="htmlhelp.encoding" select="'windows-1250'"/>
<xsl:param name="default.encoding" select="'windows-1250'"/>
<xsl:param name="charset" select="'windows-1250'"/>

</xsl:stylesheet>



I call XSL transformation

xsltproc   --nonet    ../xsl/htmlhelp/pl.xsl     mydoc.xml


and then use Windows HTML Help Workshop.

Regards
Wojtek