Freemarker template simulating xs:copy-of behavior

I am creating a data-model from XML content and am trying to use write a template that selects a node (containing child nodes) from the data-model.

final Map<String, NodeModel> root = new HashMap<String, NodeModel>();
root.put("doc", freemarker.ext.dom.NodeModel.parse(new InputSource(new StringReader(response))));

where response is:

<ns:Response xmlns:ns="urn:sdf.sdf.as.v1">
  <ns:MessageBody>
    <ns:Items>
      <ns:Item>
        <ns:ItemId>1</ns:ItemId>
      </Item>
      <ns:Item>
        <ns:ItemId>2</ns:ItemId>
      </Item>
    </ns:Items>
  </ns:MessageBody>
</ns:Response>

The template I am trying to come up with is: ${doc.Response.MessageBody.Items}

I get the following exception:

Expecting a string, date or number here, Expression doc.Response.MessageBody.Items is instead a freemarker.ext.dom.NodeListModel

What am I doing wrong? Can Freemarker Template work on an Element node or does it always have to be a node value? Could it be because my template does not contain namespaces? How do I reference namespaces?