Inheritance

Hello Torque-users,

I have problem with Inheritance and Torque. The Inheritance Guide 
(http://www.ingrid.org/jajakarta/turbine/en/turbine/torque/inheritance-guide.html)
 
describes how to define a subclass.

But I can't find a way to define extra columns for my subclass.

The example below works great, a subclass HumanResource is generated. But how 
do i get extra columns for HumanResources?

Thanks in advance,
  Christian

<table name="Resource" description="Resource">
    <column
      name="id"
      required="true"
      primaryKey="true"
      type="INTEGER"
    />
    <column
      name="name"
      type="VARCHAR"
      description="Name of this Resource"/>
    />
    <column
     name="class_type"
     type="VARCHAR"
     inheritance="single">
      <inheritance key="human_resource"
            class="HumanResource"
            extends="Resource"/>
    </column>

  <column
     name="class_type"
     type="VARCHAR"
     inheritance="single">
      <inheritance key="human_resource"
            class="HumanResource"
            extends="Resource"/>
    </column>