Ofxml addchild - can't recreate example in docs

I’ve been getting weird results using addChild, so I worked back to basics and tried to recreate the example in the online documents here
http://openframeworks.cc/documentation/utils/ofXml/#show_addChild

This is my code
void ofApp::setup()
{

    ofXml _presets;
    ofFile fileSpec;
    fileSpec.open("presetTemplate.xml");
    ofBuffer buffSpec = fileSpec.readToBuffer();
    _presets.loadFromBuffer(buffSpec);
    fileSpec.close();
    _presets.addChild("pictures/picture/views");

    string address = "test.xml";
    ofBuffer xmlOut = _presets.toString();
    ofBufferToFile(address, xmlOut);
}

presetTemplate.xml, the input, looks like this

<pictures>
    <picture id="0">
        <url>http://apicture.co.uk/pic.png</url>
        <width>100</width>
        <height>100</height>
    </picture>
</pictures>

the docs lead me to believe I should expect the output (test.xml) to look like this

<pictures>
    <picture id="0">
        <url>http://apicture.co.uk/pic.png</url>
        <width>100</width>
        <height>100</height>
        <views/>
    </picture>
</pictures>

in fact, I get this:

<pictures>
<picture id="0">
    <url>http://apicture.co.uk/pic.png</url>
    <width>100</width>
    <height>100</height>
</picture>
<pictures>

		<picture/>

	</pictures>

	<views/>

</pictures>

are the docs wrong, or am I missing something?