title: Generate class for schema with abstract complex type
body: <p>I'm working with some schema which defines an abstract complex type, eg.</p>
  
  <pre><code>&lt;xs:complexType name="MyComplexType" abstract="true"&gt;
  </code></pre>
  
  <p>This type is then referenced by another complex type in the schema:</p>
  
  <pre><code>&lt;xs:complexType name="AnotherType"&gt;
    &lt;xs:sequence&gt;
      &lt;xs:element name="Data" type="MyComplexType" maxOccurs="unbounded"/&gt;
    &lt;/xs:sequence&gt;
  &lt;/xs:complexType&gt;
  </code></pre>
  
  <p>When I run "xsd.exe /d /l:CS MySchema.xsd" I get this error:</p>
  
  <blockquote>
    <p>Error: There was an error processing MySchema.xsd'.
      - Error generating code for DataSet ''.
      - Unable to convert input xml file content to a DataSet. DataSet cannot instantiate an abstract ComplexType for the node Data.
      - DataSet cannot instantiate an abstract ComplexType for the node Data.</p>
  </blockquote>
  
  <p>It doesn't seem to be invalid schema.  Has anyone else run into this issue?</p>
  
  <p>Thanks</p>
  
  <p>Nick</p>