多次元PHP配列をXML形式データに変換する方法

多次元PHP配列をXML形式データに変換するにはどうすればよいですか?
PHP 配列は次のようになります:

array(4) <br />
{ <br />
	["auth"]=> array(3) <br />
	{<br />
		["user"]=> string(8) "customer" <br />
		["password"]=> string(8) "password" <br />
		["context"]=> string(1) "4" <br />
	} <br />
	["owner"]=> array(2) <br />
	{ <br />
		["user"]=> string(9) "customer2" <br />
		["context"]=> string(1) "4" <br />
	} <br />
	["language"]=> string(2) "en" <br />
	["task"]=> array(1) <br />
	{ <br />
		["code"]=> string(4) "0130" <br />
	} <br />
}

xml形式に変換後のデータ形式は以下の通りです:

<?xml version="1.0" encoding="utf-8"?><br />
<request><br />
	<auth><br />
		<user>customer</user><br />
		<password>password</password><br />
		<context>4</context><br />
	</auth><br />
	<owner><br />
		<user>customer2</user><br />
		<context>4</context><br />
	</owner><br />
	<language>en</language><br />
	<task><br />
		<code>0130</code><br />
	</task><br />
</request>

php 配列 xml

共有先:
-----解決策---------

 $ar=array<br />
( <br />
	"auth"=> array <br />
	(<br />
		"user"=>  "customer" ,<br />
		"password"=>  "password" ,<br />
		"context"=>  "4" <br />
	) ,<br />
	"owner"=> array <br />
	( <br />
		"user"=>  "customer2" ,<br />
		"context"=>  "4" <br />
	) ,<br />
	"language"=>  "en" ,<br />
	"task"=> array<br />
	( <br />
		"code"=>  "0130" <br />
	) <br />
);<br />
<br />
<br />
$doc = new DOMDocument('1.0','UTF-8');<br />
// we want a nice output<br />
$doc->formatOutput = true;<br />
<br />
$root = $doc->createElement('request');<br />
$root = $doc->appendChild($root);<br />
<br />
 foreach($ar as $title=>$title_v){<br />
   $title = $doc->createElement($title);<br />
   $title = $root->appendChild($title); <br />
    if(is_array($title_v)){<br />
       foreach($title_v as $k=>$v){<br />
	       $k = $doc->createElement($k);<br />
           $k = $title->appendChild($k);<br />
		   $text = $doc->createTextNode($v);<br />
           $text = $k->appendChild($text);<br />
	   } <br />
   }else{<br />
       $text = $doc->createTextNode($title_v);<br />
       $text = $title->appendChild($text);<br />
   }<br />
}<br />
<br />
echo $doc->saveXML();

-----解決策---------------------

$ar = array( <br />
	"auth" => array( <br />
		"user" => "customer",<br />
		"password" => "password",<br />
		"context" => "4",<br />
	),<br />
	"owner" => array( <br />
		"user" => "customer2",<br />
		"context" => "4",<br />
	),<br />
	"language" => "en",<br />
	"task" => array( <br />
		"code" => "0130",<br />
	), <br />
);<br />
$xml = simplexml_load_string('<request />');<br />
create($ar, $xml);<br />
echo $xml->saveXML();<br />
<br />
function create($ar, $xml) {<br />
	foreach($ar as $k=>$v) {<br />
		if(is_array($v)) {<br />
			$x = $xml->addChild($k);<br />
			create($v, $x);<br />
		}else $xml->addChild($k, $v);<br />
	}<br />
}

<?xml version="1.0" ?> <br />
<request><br />
	<auth><br />
		<user>customer</user> <br />
		<password>password</password> <br />
		<context>4</context> <br />
	</auth><br />
	<owner><br />
		<user>customer2</user> <br />
		<context>4</context> <br />
	</owner><br />
	<language>en</language> <br />
	<task><br />
		<code>0130</code> <br />
	</task><br />
</request>