Add "Post to Twitter" to comments

This seems like a natural ... I'm curious why it is not currently possible to add "Post to Twitter" to comments.

I can make the Twitter form show in the comments form, but it doesn't post despite my best efforts to add 'comment' to the $allowed_types.

Am I missing something obvious? I know that a comment is not a node, but what might be the programming issue that has kept this feature from being included?

(BTW, here's how to add it to the comments form, but it doesn't post ...)

twitter/twitter_module/twitter_module.module, line 32:

Original:
if (isset($form['#node']) && $form['#node']->type .'_node_form' == $form_id)

Modified:
if ((isset($form['#node']) && $form['#node']->type .'_node_form' == $form_id) || ($form_id == 'comment_form' && $form['form_id']['#id'] == 'edit-comment-form'))

Thanks!