title: What is the syntax for accessing child nodes using System.Xml.XmlDocument.SelectNodes with a namespace?
body: <p>Given the following XML:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;Task version="1.3" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task"&gt;
    &lt;RegistrationInfo&gt;
      &lt;Date&gt;2014-12-03T13:58:05.5136628&lt;/Date&gt;
      &lt;Author&gt;ABCCORP\jsmith&lt;/Author&gt;
    &lt;/RegistrationInfo&gt;
  &lt;/Task&gt;
  </code></pre>
  
  <p>I can access the Task node using SelectNodes as follows:</p>
  
  <pre><code>[xml]$xml = gc C:\temp\myxml.xml
  $ns = new-object Xml.XmlNamespaceManager $xml.NameTable
  $ns.AddNamespace("ns0", "http://schemas.microsoft.com/windows/2004/02/mit/task")
  $xml.SelectNodes("ns0:Task", $ns)
  </code></pre>
  
  <p>But I can't access child nodes. For example, this returns null:</p>
  
  <pre><code>$xml.SelectNodes("ns0:Task/RegistrationInfo", $ns)
  </code></pre>
  
  <p>What is the correct syntax for accessing child nodes?</p>