How to output XML schema with Services module?

I have set the REST server with the Services module.

Also I've installed the Services Views module, created a new view that outputs the desired fields into XML.

That's working fine.

How can I add XML schema to that output, so the XML will look like:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
.....  

EDIT:
In the Services module in rest_server/includes/ServicesFormatter.inc on line 44 I can see this:

class ServicesXMLFormatter implements ServicesFormatterInterface {
  public function render($data) {
    $doc = new DOMDocument('1.0', 'utf-8');
    $root = $doc->createElement('result');
    $doc->appendChild($root);

    $this->xml_recursive($doc, $root, $data);

    return $doc->saveXML();
  }

So, I guess $root = $doc->createElement('result'); has to be changed.

I've already tried to change into $root = $doc->createElement('http://www.w3.org/2001/XMLSchema', 'xs:schema'); , but it displayis XML Parsing Error: no element found.