Using Two Model Fields In One Form

In my application have two models user and address. The data saved to two tables using one form. But for validation purpose, only one model form fields are validated if all fields are empty. Means if we just submit the form without enter any data in form, the error message (like "City cannot be blank") happens only for one model. i want to display error for both models.
i checked these posts.
1. http://www.yiiframework.com/wiki/218/how-to-use-single-form-to-collect-data-for-two-or-more-models-cactiveform-and-ajax-validation-edition/
2. http://www.yiiframework.com/wiki/19/how-to-use-a-single-form-to-collect-data-for-two-or-more-models/