Cgridview With Widgets In New Row Footer

Hi,

I am new using Yii and I wonder if there is a way to add widgets to a CGridView footer. I want to build a footer that let me add new rows to the CGridView.
I am able to add Html simple controls using for example

'footer' => CHtml::textField()

But when I try to add a widget for autocomplete

'footer' => $this->widget('zii.widgets.jui.CJuiAutoComplete'...)

it returns me an error:
trim() expects parameter 1 to be string, object given

The only way is to extends CDataColumn and overridden each column with a custom class?

Thanks