title: Doctrine 1.2 ORM inherited class cant acces to its parent relations
body: <p>having the class A and the class B that inherits from A, and class C to which A has a ratio of 1: M respectively (A, C), when creating an object of the class B and trying to access form $B->C->attributeOfC throws Doctrine_Record_UnknownPropertyException 'with message' Unknown record property / related component</p>
  
  <p>A simple example in code:</p>
  
  <pre><code>//A
  class tableA extends Doctrine_Record{    
      public function setTableDefinition() {
          $this-&gt;hasColumn('tableA_id', 'integer', null, array(
              'primary' =&gt; true, 'autoincrement' =&gt; true));          
              $this-&gt;hasColumn('tableC_id','integer');
               $this-&gt;setSubclasses(array(
                  'tableB'  =&gt; array('type' =&gt; 1)
              ));  }
      function setup() {
          $this-&gt;setTableName("tableA");
          $this-&gt;hasOne('tableC', array(
              'local' =&gt; 'tableC_id',
              'foreign' =&gt; 'tableC_id'
                  ));    }
  }
  //B
  class tableB extends tableA{
     public function setTableDefinition() {
          $this-&gt;hasColumn('tableB_id', 'integer', null, array(
              'primary' =&gt; true, 'autoincrement' =&gt; true));
              $this-&gt;hasColumn('tableA_id','integer');        
      }
      function setup() {
          $this-&gt;setTableName("tableB");
      }
  }
  
  //C
  class tableC extends Doctrine_Record{   
      public function setTableDefinition() {
          $this-&gt;hasColumn('tableC_id', 'integer', null, array(
              'primary' =&gt; true, 'autoincrement' =&gt; true));
              $this-&gt;hasColumn('attributeOfC','string');
      }
      function setup() {
          $this-&gt;setTableName("tableC");
           $this-&gt;hasMany('tableA as Alias', array(
              'local' =&gt; 'tableC_id',
              'foreign' =&gt; 'tableC_id'
                  )); }
  }
   //some code where we create $objectOfCClass as an instance of tableCe
   $objectA = new $tableA(); 
   $objectA-&gt;tableC=$objectOfCClass;
   $objectA-&gt;save();
  </code></pre>