how to output new xml from existing xml with xsl

Hello
im kinda newbe here with xsl , how can i output new
xml vaild struct from existing xml struct?
so that IE will read it as xml file (the tree look ....)
thanks!!

generating XML from XML is essentially the same as generating HTML, but you can use the <xsl:output> tag to specify the DTD, encoding, etc. Check out http://www.w3schools.com/xsl/el_output.asp