var text:String = 'abc0123456789';

var a:XML = <a><![CDATA[{text}]]></a>;
trace(a.toXMLString()); // <a><![CDATA[{text}]]></a>;

var b:XML = <b>{'<![CDATA[' + text + ']]>'}</b>;
trace(b.toXMLString()); // <b><![CDATA[abc0123456789]]></b>

var c:XML = <c>{new XML('<![CDATA[' + text + ']]>')}</c>;
trace(c.toXMLString()); // <c><![CDATA[abc0123456789]]></c>