Open Contact form link with Lightbox2?

Hello.

I would like to open Contact form via Lightbox2. It requires to append *rel* tag to link. Using Zen theme I tried to override *theme_email_formatter_contact* in my template.php, but due to lack of brains in my head (smile), was unable to do this even after googling around "add href class via template.php site:drupal.org". Now I have this in my template.php:

function zen_email_formatter_contact($element) {
  return !empty($element['#item']['safe']) ? l(t('Send message'), 'email/'. $element['#node']->nid .'/'. $element['#field_name']) : '' ;
}

But how can I add *rel=* tag to here?

Thank you for help and your time!