UTF-8 chars in XSL output?

Hi again; I've narrowed my problem down, if you're following:

I have a UTF-8 XML file with unusual characters (left and right 
double-quotes).  

If I set <xsl:output encoding="US-ASCII"/>, I see the quotes; 
if I let it default to UTF-8, I don't.

Does this mean that my source XML is *not* UTF-8, as Perl's
Unicode::String::utf8 claims it to be?

Thanks in anticipation,
lee

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