xslt transformation and encoding

Dear math group,

i have some xhtml+MATHML document test.xml that is encoded in ISO-8859-
1 (it contains some accented characters).
I'd like to transform it to test.tex to process it with latex.

I can't find how to output test.tex's encoding :

if i use <xsl:output encoding="UTF-8"/>, and \usepackage[utf8]
{inputenc},
latex doesn't recognize anything (i use last miktex distribution under 
windows);

if i use <xsl:output encoding="ISO-8859-1"/>, and \usepackage[latin-1]
{inputenc}, the transformation doesn't terminate using saxon because 
some mathml entities are not ISO-8859-1 characters (&rarr; for 
instance : however, if test.xml doesn't contains any of those "extra" 
characters, all the process goes well).

So what are the correct parameters ?

Thanks for any hint or link,
Stephan