title: XML can't write xmlns to child nodes
body: <p>Hi I have 3 classes like that:</p>
  
  <pre><code>public abstract class XmlNs
  {
      public const string XmlnsAttribute = "urn:ebay:apis:eBLBaseComponents";
  }
  
  
  [Serializable]
  public class BulkDataExchangeRequests : XmlNs
  {
      [XmlAttribute("xmlns")]
      public string XmlNs = XmlnsAttribute;
      [XmlElement("Header")]
      public Header Header { get; set; }
      [XmlElement("AddFixedPriceItemRequest")]
      public List&lt;AddFixedPriceItemRequest&gt; ListAddFixedPriceItemRequest { get; set; }
  }
  
  [Serializable]
  public class AddFixedPriceItemRequest : XmlNs
  {
      [XmlElement("ErrorLanguage")]
      public string ErrorLanguage { get; set; }
      [XmlElement("WarningLevel")]
      public string WarningLevel { get; set; }
      [XmlElement("Version")]
      public string Version { get; set; }
      [XmlElement("Item")]
      public ItemType Item { get; set; }
      [XmlAttribute("xmlns")]
      public string XmlNs = XmlnsAttribute;
  }
  </code></pre>
  
  <p>The problem is that when I serialize the object I get a correct xml but with no xmlns attribute in the AddFixedPriceItemRequest item, while in the BulkDataExchangeRequests the xmlns is correctly written....</p>
  
  <p>Any help will be very appreciated...</p>