WordPress hooks with parameters function don't work

I need add an action that retrieves a parameter. I have this:

add_action('dopbsp_reservation_approve_hilo', array(&$this->classes->backend_reservation, 'approve_hilo'), 1, 1);
//add_action('wp_ajax_dopbsp_reservation_approve_hilo', array(&$this->classes->backend_reservation, 'approve_hilo'), 1, 1); tested to, same result
do_action('dopbsp_reservation_approve_hilo',  $reservation_id); //I had confirmed that $reservation_id has the correct value

And my function is declared this way:

function approve_hilo($reservation_id){
//my stuff goes here...
}

But approve_hilo function is never called. Do you know what is wrong?

thanks you all in advance!