wysiwyg on form textareas

Hi. One of my modules needs textarea input, and I am mainly going to input HTML so was wondering if there a way to apply wysiwyg to a textarea other than the body of a content type... I see many issues saying how do we stop this happening, but none saying how do we start it happening :)

$form['this_text_info'] = array(
		'#type' => 'textarea',
		'#title' => t('Information to appear at top of page, may use full HTML'),
		'#cols' => 60,
		'#rows' => 5,
		'#required' => TRUE
	);

I'm not sure if the problem is in my form setup, so I add it here.