negli xml esistono le entitą cosi come esistono in html.

In genere si usa o il CDATA (ma vale per il contenuto del tag) e allora ci puoi mettere qualsiasi cosa dentro, oppure converti

< in &amp;lt;
> in &amp;gt;
& in &amp;amp;

Se non sbaglio sono le uniche entitą supportate da xml.

Quindi teoricamente devi trasformare il tuo tag in:

codice:
<function pattern="abstract" doctypes="PHP_MySQL" displayrestriction="PHP_Script" caseSensitive="true"  icon="shared/mm/images/hintKeyword.png"  MMString:source="php/CORE" description="&amp;lt;div class='refentry refnamediv'&amp;gt; &amp;lt;a class='info-url' href='http://www.php.net/manual/en/language.oop5.abstract.php'&amp;gt;&amp;lt;h1 class='refname'&amp;gt;abstract&amp;lt;/a&amp;gt;&amp;lt;/h1&amp;gt; &amp;lt;p class='verinfo'&amp;gt;(PHP 5)&amp;lt;/p&amp;gt; &amp;lt;p class='refpurpose'&amp;gt;&amp;lt;span class='refname'&amp;gt;abstract&amp;lt;/span&amp;gt; — &amp;lt;span class='dc-title'&amp;gt;Keyword&amp;lt;/span&amp;gt;&amp;lt;/p&amp;gt; &amp;lt;/div&amp;gt;&amp;lt;div class='copyright-info'&amp;gt;PHP Documentation is licensed under the &amp;lt;a class='copyright-url' href='http://creativecommons.org/licenses/by/3.0/legalcode'&amp;gt;Creative Commons  Attribution 3.0 License&amp;lt;/a&amp;gt;. © 2001-2009 the PHP  Documentation Group.&amp;lt;/div&amp;gt;"/>
ciao