public function addRole($name)
    {
        $namespaceUri = $this->dom->lookupNamespaceUri($this->dom->namespaceURI);

        $roleNode = $this->dom->createElementNS($namespaceUri, 'Role');
        $roleNode->setAttribute('name', $name);

        $instancesNode = $this->dom->createElementNS($namespaceUri, 'Instances');
        $instancesNode->setAttribute('count', '2');

        $configurationSettings = $this->dom->createElementNS($namespaceUri, 'ConfigurationSettings');

        $roleNode->appendChild($instancesNode);
        $roleNode->appendChild($configurationSettings);

        $this->dom->documentElement->appendChild($roleNode);

        $this->save();
    }