Additional criteria to symfony filter - symfony1

Question

i'm working on a symfony project to manage a database. First i explain how it works:
In the database, all elements are associated to an unique element 'scene'. When a user accesses the application, chooses what scene he wants to see (it saves that in a user parameter). So when listing elements, the application should only list elements associated with the scene selected by the user.
*Note: all elements have an scene attribute in the table definition.
So my problem comes here:
I developed a listing of an element entities using the help of a sfPropelPager class to paginate. Also added some filters to search in the list, and for that i used the filter system provided by symfony (<element>FormFilter.class.php and stuff).
Now i want the list to not show elements from other scenes than the selected by the user.
How can i do to add additional criteria to the criteria given by the filter class?
or How would you solve the problem?
here is my action code:
public function executeUnidadfilter(sfWebRequest $request){
$this->filter = new BaUnidadorganizativaTblFormFilter();
$c = $this->filter->getCriteria();
$this->filter->bind($request->getParameter($this->filter->getName()));
if($this->filter->isValid()){
$this->pager = new sfPropelPager('BaUnidadorganizativaTbl',$this->sfPropelPagerLines);
echo $this->getUser()->getEscenario();
$this->pager->setCriteria($c);
$this->pager->init();
}else{
$this->pager = new sfPropelPager('BaUnidadorganizativaTbl',$this->sfPropelPagerLines);
$this->pager->init();
}
$this->setTemplate('Unidadlist');
}
*Note: 'scene' mentioned below is Escenario in the code
thank you very much for your time

Answer 1

I solved the problem. The trouble was that i assigned the formfilter generated criteria to my criteria var Before the filter was filled. That's why of the error.
The resulting code is that:
public function executeUnidadfilter(sfWebRequest $request){
$this->filter = new BaUnidadorganizativaTblFormFilter();
$this->filter->bind($request->getParameter($this->filter->getName()));
if($this->filter->isValid()){
$this->pager = new sfPropelPager('BaUnidadorganizativaTbl',$this->sfPropelPagerLines);
$esc = $this->getUser()->getEscenario();
$c = new Criteria();
$c = $this->filter->getCriteria();
$c->addAnd('codigo_escenario',$esc);
$this->pager->setCriteria($c);
$this->pager->init();
}else{
$this->pager = new sfPropelPager('BaUnidadorganizativaTbl',$this->sfPropelPagerLines);
$this->pager->setCriteria($this->filter->getCriteria());
$this->pager->init();
}
$this->message=null;
$this->messageType=null;
$this->setTemplate('Unidadlist');
}