JForm/setField, как использовать параметр group, нужен пример - Разработка расширений для Joomla 2.5

$field = new SimpleXMLElement( '<field type="text" name="test" label="test"/>' );
$form->setField( $field, 'params' );

JForm::addFormPath( __DIR__ . '/fields' );
$form->loadFile( 'add', false );

<?xml version="1.0" encoding="utf-8"?>
<form>
    <fields name="attribs">
        <fieldset name="basic" label="COM_CONTENT_ATTRIBS_FIELDSET_LABEL">
            <field name="field1" type="text" label="Title:" value=""></field>
        </fieldset>
    </fields>
</form>

ul class="adminformlist">
	<?php foreach ($this->form->getFieldset('properties') as $field) : ?>
	<li>
		<?php echo $field->label; ?>
		<?php echo $field->input; ?>
	</li>
	<?php endforeach; ?>
</ul>

	<fields name="properties">
		<fieldset name="properties">
		
		</fieldset>
	</fields>

$form->setField($element, 'properties')

<ul class="adminformlist">
	<?php foreach ($this->form->getFieldset('properties') as $field) : ?>
	<li>
		<?php echo $field->label; ?>
		<?php echo $field->input; ?>
	</li>
	<?php endforeach; ?>
</ul>

	public function getForm( $data = array(), $loadData = true )
	{
		$xmlData = 'Тут пихаете всю XML-ку в виде строки и при каком то условии можете менять данные';
		$form = $this->loadForm( $xmlData, $xmlData, array( 'control' => 'jform', 'load_data' => $loadData ) );
		if ( empty( $form ) ) {
			return false;
		}
		return $form;
	}

$xmlform = new SimpleXMLElement('<form />');
$xmlfields = $xmlform->addChild('fields');
$xmlfields->addAttribute('name', 'properties');
$xmlfieldset = $xmlfields->addChild('fieldset');
$xmlfieldset->addAttribute('name', 'properties');
$xmlfield = $xmlfieldset->addChild('field');
$xmlfield->addAttribute('name', 'property');
$xmlfield->addAttribute('type', 'text');
$xmlfield->addAttribute('label', 'COM_REALTY_FIELD_PROPERTY_LABEL');
if (!$form->load($xmlform))
{
	die('Ошибка');
}

$item_id = $this->state->get('item.id'); //Получили id элемента