I think I got the solution!

gistfile1.aw

<?php

class foo extends CActiveRecord
{
    public function save($runValidation=true,$attributes=null)
    {
        if( Yii::app()->db->getCurrentTransaction() === null )
        {
            $transaction = Yii::app()->db->beginTransaction();
            $transaction->attachbehavior('modelSaveTransaction', new CBehavior);
            tr('This transaction is owned by an IcsActiveRecord->save');
        }        
        
        $currentTransaction = Yii::app()->db->getCurrentTransaction();
        if (!isset($currentTransaction->modelSaveTransaction))
        {
            tr('This save is called in an outside transaction, not owned by IcsActiveRecord->save.');
            if (!isset($currentTransaction->firstSaveIsCalled))
            {
                $currentTransaction->attachbehavior('firstSaveIsCalled', new CBehavior);
                $startedTheSave = true;
            }            
        }
        
        try {
            
            parent::save($runValidation, $attributes);
            if(!empty($this->relationsHolder))
                $this->relatedSave($runValidation);     //this function also calls foo::save()

            if($this->hasErrors())
            {
                throw new CDbException('Model(s) do not pass validation.');
            }                
            else
            {
                if(isset($transaction))
                    $transaction->commit();
                return true;
            }
            
        }
        catch (Exception $e)
        {
            if(isset($transaction))
                $transaction->rollback();
            else if (isset($startedTheSave))
                throw $e;

            tr('Class: '.get_class($this) .'. '.'Exception in save() catched! '.$e->getMessage());
            return false;
        }
    }
}

####################################################

# CONTROLLER A works

   public function actionUpdateA($id)
    {
        $model=$this->loadModel($id);
        
        // Uncomment the following line if AJAX validation is needed
        // $this->performAjaxValidation($model);

        if(isset($_POST['Incident']))
        {
            $model->attributes=$_POST['Incident'];
            $model->setRelatedData('kanalen');
            $model->setRelatedData('dienstenVerstoord');
            $model->setRelatedData('nrns');
            $model->setRelatedData('postcodes');
            $model->setRelatedData('plaatsen');
            $model->setRelatedData('overigeLocaties');
 
            if($model->save())
                   $this->redirect(array('view','id'=>$model->id));
        }

        $this->render('update',array(
            'model'=>$model,
        ));
    }

# CONTROLLER B works

   public function actionUpdateB($id)
    {
        $model=$this->loadModel($id);
        
        // Uncomment the following line if AJAX validation is needed
        // $this->performAjaxValidation($model);

        if(isset($_POST['Incident']))
        {
            $model->attributes=$_POST['Incident'];
            $model->setRelatedData('kanalen');
            $model->setRelatedData('dienstenVerstoord');
            $model->setRelatedData('nrns');
            $model->setRelatedData('postcodes');
            $model->setRelatedData('plaatsen');
            $model->setRelatedData('overigeLocaties');
            
             $transaction = Yii::app()->db->beginTransaction();
             try {
                
            
                if($model->save())
                       $this->redirect(array('view','id'=>$model->id));
            
             } catch (Exception $e)
             {
                 $transaction->rollback();
                 tr('Catched by controller');
             }
            
        }

        $this->render('update',array(
            'model'=>$model,
        ));
    }

?>