Mimemail ignores attachment on subsequent sending of the same message

The following code illustrates my problem. I'm sending a node with file attachments as an email message. The first recipient (first call to mimemail) will receive the attachment but it will not be sent to the rest. A quick look in mimemail.inc reveals some use of static variables for attachments. I guess it may be the reason for this.
Code:

//This is my send function
function send_node($node, $recipient) {
  $message = new stdClass();
  $message->sender     = 'ourmail@ourdomain.no' ;
  $message->recipient  = trim($recipient);
  $message->subject    = $node->title;
  $message->body       = $node->body;
  $message->plaintext  = FALSE;
  $message->headers    = array();
  $message->text       = strip_tags($node->body);
  $message->attachments = array();
  foreach($node->files as $id => $file) {
	$message->attachments[] = array('filepath' => $file->filepath, 'filemime' => $file>filemime);
  }	
  return mimemail(
    $message->sender,
    $message->recipient,
    $message->subject,
    $message->body,
    $message->plaintext,
    $message->headers,
    $message->text,
    $message->attachments
    );
}

// I use it like this
$q = "SELECT email FROM mydata";
$result = db_query($q);
while ($obj = db_fetch_object($result)) {
	$node = node_load(5386);
	$sr = send_node($node, $obj->email);
}