I need to create a valid xml from a given array();

My Method looks like this,

protected function array2Xml($array)
    {
        $xml = "";

        if(is_array($array))
        {
            foreach($array as $key=>$value)
            {
                $xml .= "<$key>";

                if(is_array($value))
                {
                    $xml .= $this->array2Xml($value);
                }
                $xml .= "</$key>";
            }

            return $xml;
        }
        else
        {
            throw new Exception("in valid");
        }
    }


protected function createValidXMLfromArray($array,$node)
    {
        $xml = '<?xml version="1.0" encoding="ISO-8859-1"?>';

        $xmlArray = $this->array2Xml($array);

        $xml .= "<$node>$xmlArray</$node>";
        return $xml;
    }

if i execute the above i just get keys with empty values;

like

<node>
<name></name>
</node>

What i need is if i pass this array("name"=>"test","value"=>array("test1"=>33,"test2"=>40));

that it return this

<node>
<name>test</name>
<value>
<test1>33</test1>
<test2>40</test2>
</value>
</node>

Where is the error what did i wrong in the above recursion?