How you can post validate embedded forms

ExampleForm.class.php

class TestForm
{
  public function configure()
  {
    // ... snip ...

    $eForm = new SomeObjectEmbeddedForm($this->getObject()->SomeObject);
    $this->embedForm('some_object', $eForm); 

    $this->validatorSchema->setPostValidator(
      new sfValidatorCallback(array('callback' => array($this, 'contextualChecks')))
    );
  }
 
  public function contextualChecks($validator, $values)
  {
    if ($values['some_object']['some_checkbox'] == 1 && $values['some_object']['some_field'] == '')
    {
      $error = new sfValidatorError($validator, 'Field is required when Checkbox 1 is checked.');
      $ves = new sfValidatorErrorSchema($validator, array('some_field' => $error));
      throw $ves;
    }
    return $values;
  }
}