XSL Stylesheets - use to change encoding value?

Hello,

Currently, the encoding for our cXML PO document is US-ASCII.  I have seen some indications on the web that encoding can be changed with an xsl stylesheet, as shown below:

    <!-- BBMsc.xsl -->

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

    <xsl:output method="xml" indent="yes" encoding="UTF-8"/>

    </xsl:stylesheet>

My tests are generating an xml document, but without any encoding at all.  My utlimate goal is to do most of the mapping using message designer with the .xgm file and then just use the stylesheet to alter encoding.  I could use some good references on how to create a stylesheet - as I am unfamiliar with the syntax.