All white space and newlines are being removed from contact messages

My customers have been heavily using the personal contact forms on my site. I am getting a lot of complaints that all of their return characters are getting stripped from their messages. I believe it might be related to this:
http://drupal.org/node/298708
which leads me to believe it may be a call to drupal_html_to_text() by drupal mail. Could it be that it is assuming that the message field is html when it is not?

I've tried to address the problem by adding a wysiwyg editor to the message field. I did this by using hook_form_alter, changing the message type from 'textarea' to 'text_format':

function _form_alter(&$form, &$form_state, $form_id) {
if ($form_id == 'contact_personal_form') {
$form['message']['#type']='text_format';
}
}

This made text editor (tinymce) appear in the message field, but gave this error when the message was sent:

I would really appreciate any pointers on how to allow users to send contact messages without all whitespace/newlines being stripped away.

Kari