Change encoding attribute after XLST

I've done some transformation my DXL using XSLT. The funny thing was that after transformation using

// Transform
var str = docxml.transformNode(xsl);

I always got 'encoding' as UTF-16, that's not correct, so after some time I found nice solution

here is code I used: http://dotnet.itags.org/dotnet-tech/66097/

var doc = new ActiveXObject("Microsoft.XMLDOM");
doc.load("test.xml");

// Print initial encoding
var pi = doc.firstChild;
var eattr = pi.attributes.getNamedItem("encoding");
var encoding = eattr.value;

// Convert to string and reload (this loses the encoding)
var xml = doc.xml;
doc.loadXML(xml);

// Reset the encoding to "ISO-8859-1"
pi = doc.firstChild;
var eattr = pi.attributes.getNamedItem("encoding");
if (eattr == null) {
eattr = doc.createAttribute("encoding");
pi.attributes.setNamedItem(eattr);
}
eattr.value = "ISO-8859-1";

// And save document with new encoding.
doc.save("test2.xml");

It works fine for me (and not, output option in XSL did not help)