E4X Add CDATA content

Basically I need to define a node name and its CDATA content using variables.

var nodeName:String = "tag";
var nodeValue:String = "<non-escaped-content>";

Naively I thought this would work :

var xml:XML = <doc><{nodeName}><![CDATA[{nodeValue}]]></{nodeName}>

Outputs :

<doc><tag><![CDATA[{nodeValue}]]></tag></doc>

In a previous version of the script designed for FP9 I bypassed the problem by using :

new XMLNode( XMLNodeType.XMLNodeType.CDATA_NODE, nodeValue ); // ...

but this doesn't seem to work in FP10, and I have the feeling the method is somehow depreciated anyway.

Anyone an elegant solution for this ?