PHP parse XML within XML

I have an XML file that contains XML within it. How would I go about parsing everything into an array or object?

<DATA>
    <ROW>
        <id>1</id>
        <message_id>123456789</message_id>
        <brand_name>SAMPLE</brand_name>
        <request_xml>
&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;Email&gt;
&lt;Service&gt;
&lt;LogMessage/&gt;
&lt;Delivery&gt;
&lt;Synchronous/&gt;
&lt;/Delivery&gt;
&lt;/Service&gt;
&lt;Model&gt;
&lt;Head&gt;
&lt;From&gt;someone@example.com &lt;/From&gt;
&lt;To&gt;someone@sample.com&lt;/To&gt;
&lt;Subject&gt;Your Question&lt;/Subject&gt;
&lt;/Head&gt;
&lt;ns2:ContactUs&gt;
&lt;ns2:Sender&gt;
&lt;ns2:FirstName&gt;John&lt;/ns2:FirstName&gt;
&lt;/ns2:Sender&gt;
&lt;/ns2:ContactUs&gt;
&lt;/Model&gt;
&lt;InlineImages/&gt;
&lt;History/&gt;
&lt;/Email&gt;
        </request_xml>
        <http_status>400</http_status>
        <created_by>admin</created_by>
        <created_on>2014-09-08 01:56:59</created_on>
    </ROW>
</DATA>

My goal is to end up with somthing like that:

SimpleXMLElement Object
(
    [ROW] => SimpleXMLElement Object
        (
            [id] => 1
            [message_id] => 123456789
            [brand_name] => SAMPLE
            [request_xml] => SimpleXMLElement Object
                (
                    ...
                    [LogMessage] => 
                    ...
                    [from] => someone@example.com
                    ...
                )

            [http_status] => 400
            [created_by] => admin
            [created_on] => 2014-09-08 01:56:59
        )
)

I didn't put all levels of the request_xml in my example, but you get the idea. Basically I want that request_xml to be parsed like the rest of the XML file.

How could I achieve this? Thanks in advance for any help on this!