title: XSD for XML with namespaced and no namespace elements combined
body: <p>I receive this kind of XML:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;root-element xmlns="SomeSpecificNameSpace"&gt;
      &lt;some-elements /&gt;
      &lt;some-other-elements/&gt;
      &lt;some-other-other-element/&gt;
      &lt;element-with-empty-namespace xmlns=""/&gt;
  &lt;/root-element&gt;
  </code></pre>
  
  <p>I must make a check that I've this <code>element-with-empty-namespace</code>, but that I don't care about the content, so I tried the following:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8" ?&gt;
  &lt;xs:schema          targetNamespace="SomeSpecificNameSpace"
                      elementFormDefault="qualified"
                      xmlns="SomeSpecificNameSpace"
                      xmlns:xs="http://www.w3.org/2001/XMLSchema"&gt;
      &lt;xs:element name="MyRootElement"&gt;
          &lt;xs:complexType&gt;
              &lt;xs:sequence&gt;
              &lt;!-- Others types here --&gt;
              &lt;/xs:sequence&gt;
          &lt;/xs:complexType&gt;           
      &lt;/xs:element&gt;
      &lt;xs:element name="element-with-empty-namespace" minOccurs="0" maxOccurs="1" xmlns=""&gt;
          &lt;xs:complexType&gt;
              &lt;xs:sequence&gt;
                  &lt;xs:any minOccurs="0" maxOccurs="unbounded" /&gt;
              &lt;/xs:sequence&gt;
              &lt;xs:anyAttribute/&gt;
          &lt;/xs:complexType&gt;
      &lt;/xs:element&gt;
  &lt;/xs:schema
  </code></pre>
  
  <p>but it seems it doesn't accept my element, saying that it is expecting an element with the namespace <code>SomeSpecificNameSpace</code>.</p>
  
  <p>I know that this structure is a little bit weird, but this <code>element-with-empty-namespace</code> is one "value" we provide through XML.</p>