// Override theme_button
function phptemplate_button($element) {
  // Make sure not to overwrite classes.
  if (isset($element['#attributes']['class'])) {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'] .' '. $element['#attributes']['class'];
  }
  else {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'];
  }

  if ($element['#id'] == 'my_id') {
  $my_type = 'button';
  }
  else {
   $my_type = 'submit';

  }

  // We here wrap the output with a couple span tags
  return '<span class="button"><span><input type="'. $my_type .'"'. (empty($element['#name']) ? '' : 'name="'. $element['#name'] .'" ')  .'id="'. $element['#id'].'" value="'. check_plain($element['#value']) .'" '. drupal_attributes($element['#attributes']) ." /></span></span>\n";
}