I'm reading in a Kml file, changing the placemarks' names, and saving it again.

var KmlFile = XDocument.Load("C:\\Inetpub\\wwwroot\\GeotagService\\Kml\\Photographs.kml");

XNamespace KmlNamespace = "http://www.opengis.net/kml/2.2";

// find the Placemarks in the Photos folder
IEnumerable<XElement> Placemarks = KmlFile.Element(KmlNamespace + "kml").Element(KmlNamespace + "Document").Element(KmlNamespace + "Folder").Elements(KmlNamespace + "Placemark");

foreach (XElement p in Placemarks){
    p.Element(KmlNamespace + "name").Value = "testing";
}

KmlFile.Save("C:\\Inetpub\\wwwroot\\GeotagService\\Kml\\Photographs.kml");

When I save it however, every element is prefixed with <kml:, like this:

<kml:Folder>
  <kml:name>Photos</kml:name>
  <kml:open>1</kml:open>
  <kml:Placemark>
    <kml:name>testing</kml:name>
    <kml:LookAt>
      <kml:longitude>-10.02717694938161</kml:longitude>
      <kml:latitude>53.48672543547379</kml:latitude>
      <kml:altitude>0</kml:altitude>
    </kml:LookAt>
    <kml:styleUrl>#msn_ylw-pushpin1</kml:styleUrl>
    <kml:Point>
       <kml:coordinates>-10.02867619360582,53.48651240326751,0</kml:coordinates>
    </kml:Point>
 </kml:Placemark>...

Tomalak's comment on this question about blank xmlns gives me a clue that it might be inconsistencies between the namespaces of the document and the elements, but I can't see how I'm doing that. Anyone know?