I am trying to change the input type on an uber cart checkout form using hook form alter. I added an extra field using the uc cart extra fields pane module but there is no option to add e-mail - only text - and I need the field I added to validate as an e-mail. 

The field in question is:
`<input type="text" id="edit-panes-billing-address-billing-ucxf-bill-to-email" name="panes[billing][address][billing_ucxf_bill_to_email]" value="" size="32" maxlength="255" class="form-text required">`

The code I am using but with no sucess is:

`    function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'uc-cart-checkout-form') {
     $form['panes-billing-address-billing-ucxf-bill-to-email'][LANGUAGE_NONE][0]['type'] = 'email';}`

Thanks for any assistance!