Zend Framework. How to add extra class to label

[gustos]

My problem is after the form has been generated, the label class has assigned to a default which is optional and the html code looks like this:\[code\]<div class="form_wrapper"> <label for="email" class="optional">Username(e-mail):</label> <input type="text" name="email" id="email" value=""></div>\[/code\]My zend code inside action is:\[code\]$form->addElement('text', 'email');$usernameElement = $form->getElement('email');$usernameElement->setLabel('Username(e-mail):');$usernameElement->setDecorators(array( 'ViewHelper', 'Label', new Zend_Form_Decorator_HtmlTag(array('tag' => 'div','class'=>'form_wrapper')) ));\[/code\]But in some case, I want it to be set as a different value that I can easily style in css. The html code I want is this(get rid of "optional"):\[code\]<div class="form_wrapper"> <label for="email" class="email_label">Username(e-mail):</label> <input type="text" name="email" id="email" value=""></div>\[/code\]