Relations Btn 2 Table: Belongs_To And Has_One

Yii version 1.1.8

I have 2 tables with a basic relationship: BELONGS_TO and HAS_ONE

The main table data is returned but the linked table data is not.

Please see attached file for ActiveRecord models and database schema

The linked table needed to be added to the criteria in the controller.

class VinController extends ApiController {

    $criteria->with = array('epa');

    $model = Vin::model()->find($criteria);