Problems with DOM Parsing/Serialization and character encodings?

Are there any issues using Mozilla DOM Parsing or Serialization and
character encodings?

For example, using Cyrillic characters via numeric entity references
(I hope I have that term correct) in an ISO-8859-1 document:

   var text = "Выбрать";
   var xml = "<?xml version='1.0' encoding='ISO-8859-1'?>\n<test>" +
text + "</test>";
   window.alert (xml);

This outputs the string exactly as you would expect, with the numeric
characters intact.

If I then make an XMLDocument out of the text, and print the value of
the text node:

   var originalDoc = new DOMParser().parseFromString(xml, "text/xml");
   window.alert (originalDoc.documentElement.childNodes[0].data);

then I see the actual Cyrillic characters. I'll paste them in here,
but I don't know how successful that will be:
&#1042;&#1099;&#1073;&#1088;&#1072;&#1090;&#1100;

I think that's still correct.

Then if I serialize it back to a string and print the result, the
numeric character entity references are gone, I still have the
Cyrillic characters, and the XML declaration still has an encoding of
ISO-8859-1:

   var serializedDoc = new XMLSerializer().serializeToString
(originalDoc);
   window.alert (serializedDoc);

<?xml version="1.0" encoding="ISO-8859-1"?>
<test>&#1042;&#1099;&#1073;&#1088;&#1072;&#1090;&#1100;</test>

That looks wrong to me. Any opinions?

Matthew Wilsno