XML : How to generate namespace prefixed xml elements using SimpleXMLElement in PHP

I'm trying to generate an RSS feed using PHP SimpleXMLElement, the problem is that i need to prefix elements and can't find a way to do this using the SimpleXMLElement class.

I've tried using $item->addChild('prefix:element', 'value') but in the result xml it strips the prefix, any idea why this happens ?.

I wonder if there is a way to solve this using the SimpleXMLElement or any other cleaner way than just echoing the XML.

For clarification, this is my PHP code:

      $xml = new SimpleXMLElement('<rss version="2.0" xmlns:g="http://base.google.com/ns/1.0"/>');      $channel = $xml->addChild('channel');      $channel->addChild('title', 'Text');      $channel->addChild('link', 'http://example.com');      $channel->addChild('description', 'An example item from the feed.');        foreach($this->products as $product) {          $item = $channel->addChild('item');            foreach($product as $key => $value)              $item->addChild($key, $value);      }        return $xml->asXML();    

And this is the example XML:

  <?xml version="1.0"?>  <rss xmlns:g="http://base.google.com/ns/1.0" version="2.0">  <channel>      <title>Test Store</title>      <link>http://www.example.com</link>      <description>An example item from the feed</description>        <item>          <g:id>DB_1</g:id>          <g:title>Dog Bowl In Blue</g:title>          <g:description>Solid plastic Dog Bowl in marine blue color</g:description>          ...      </item>  ...    

Thanks in advance