Aggiungere all’xml il seguente doctype:
  <!DOCTYPE newsletter [
  <!ENTITY tilde "& #130;">
  <!ENTITY florin "& #131;">
  <!ENTITY elip "& #133;">
  <!ENTITY dag "& #134;">
  <!ENTITY ddag "& #135;">
  <!ENTITY cflex "& #136;">
  <!ENTITY permil "& #137;">
  <!ENTITY uscore "& #138;">
  <!ENTITY OElig "& #140;">
  <!ENTITY lsquo "& #145;">
  <!ENTITY rsquo "& #146;">
  <!ENTITY ldquo "& #147;">
  <!ENTITY rdquo "& #148;">
  <!ENTITY bullet "& #149;">
  <!ENTITY endash "& #150;">
  <!ENTITY emdash "& #151;">
  <!ENTITY trade "& #153;">
  <!ENTITY oelig "& #156;">
  <!ENTITY Yuml "& #159;">
  <!ENTITY nbsp "& #160;">
  <!ENTITY iexcl "& #161;">
  <!ENTITY cent "& #162;">
  <!ENTITY pound "& #163;">
  <!ENTITY curren "& #164;">
  <!ENTITY yen "& #165;">
  <!ENTITY brvbar "& #166;">
  <!ENTITY sect "& #167;">
  <!ENTITY uml "& #168;">
  <!ENTITY copy "& #169;">
  <!ENTITY ordf "& #170;">
  <!ENTITY laquo "& #171;">
  <!ENTITY not "& #172;">
  <!ENTITY shy "& #173;">
  <!ENTITY reg "& #174;">
  <!ENTITY macr "& #175;">
  <!ENTITY deg "& #176;">
  <!ENTITY plusmn "& #177;">
  <!ENTITY sup2 "& #178;">
  <!ENTITY sup3 "& #179;">
  <!ENTITY acute "& #180;">
  <!ENTITY micro "& #181;">
  <!ENTITY para "& #182;">
  <!ENTITY middot "& #183;">
  <!ENTITY cedil "& #184;">
  <!ENTITY sup1 "& #185;">
  <!ENTITY ordm "& #186;">
  <!ENTITY raquo "& #187;">
  <!ENTITY frac14 "& #188;">
  <!ENTITY frac12 "& #189;">
  <!ENTITY frac34 "& #190;">
  <!ENTITY iquest "& #191;">
  <!ENTITY Agrave "& #192;">
  <!ENTITY Aacute "& #193;">
  <!ENTITY Acirc "& #194;">
  <!ENTITY Atilde "& #195;">
  <!ENTITY Auml "& #196;">
  <!ENTITY Aring "& #197;">
  <!ENTITY AElig "& #198;">
  <!ENTITY Ccedil "& #199;">
  <!ENTITY Egrave "& #200;">
  <!ENTITY Eacute "& #201;">
  <!ENTITY Ecirc "& #202;">
  <!ENTITY Euml "& #203;">
  <!ENTITY Igrave "& #204;">
  <!ENTITY Iacute "& #205;">
  <!ENTITY Icirc "& #206;">
  <!ENTITY Iuml "& #207;">
  <!ENTITY ETH "& #208;">
  <!ENTITY Ntilde "& #209;">
  <!ENTITY Ograve "& #210;">
  <!ENTITY Oacute "& #211;">
  <!ENTITY Ocirc "& #212;">
  <!ENTITY Otilde "& #213;">
  <!ENTITY Ouml "& #214;">
  <!ENTITY times "& #215;">
  <!ENTITY Oslash "& #216;">
  <!ENTITY Ugrave "& #217;">
  <!ENTITY Uacute "& #218;">
  <!ENTITY Ucirc "& #219;">
  <!ENTITY Uuml "& #220;">
  <!ENTITY Yacute "& #221;">
  <!ENTITY THORN "& #222;">
  <!ENTITY szlig "& #223;">
  <!ENTITY agrave "& #224;">
  <!ENTITY aacute "& #225;">
  <!ENTITY acirc "& #226;">
  <!ENTITY atilde "& #227;">
  <!ENTITY auml "& #228;">
  <!ENTITY aring "& #229;">
  <!ENTITY aelig "& #230;">
  <!ENTITY ccedil "& #231;">
  <!ENTITY egrave "& #232;">
  <!ENTITY eacute "& #233;">
  <!ENTITY ecirc "& #234;">
  <!ENTITY euml "& #235;">
  <!ENTITY igrave "& #236;">
  <!ENTITY iacute "& #237;">
  <!ENTITY icirc "& #238;">
  <!ENTITY iuml "& #239;">
  <!ENTITY eth "& #240;">
  <!ENTITY ntilde "& #241;">
  <!ENTITY ograve "& #242;">
  <!ENTITY oacute "& #243;">
  <!ENTITY ocirc "& #244;">
  <!ENTITY otilde "& #245;">
  <!ENTITY ouml "& #246;">
  <!ENTITY oslash "& #248;">
  <!ENTITY ugrave "& #249;">
  <!ENTITY uacute "& #250;">
  <!ENTITY ucirc "& #251;">
  <!ENTITY uuml "& #252;">
  <!ENTITY yacute "& #253;">
  <!ENTITY thorn "& #254;">
  <!ENTITY yuml "& #255;">
]>

Se la produzione dell’xml è fatta da un xsl ricordarsi di chiudere il tutto in un:
<xsl:text disable-output-escaping="yes"><![CDATA[...]]></xsl:text>