Display private message form in block with prepopulated and hidden To field

I think Kevin have found the solution here but there is a little problem with the solution which he mentioned it there but I can not figure it out. here is the kevin's solution:

$recipient = user_load($vars['uid']);
$subject = 'Question about your listing';
module_load_include('pages.inc','privatemsg');
$contact = drupal_get_form('privatemsg_new', $recipient, $subject);

Kevin suggests this for the v7. This does not print the form. He says in this tread that he forgot to use $vars['contact'].
Is this gonna work on v6 too. What is the correct codes for this one?

Nothing new?

Ok, I have found a sulotion:

<?php
global $user;
module_load_include('pages.inc','privatemsg');
$args[0] = arg(1);
$node_id = $args[0];
$node = node_load($node_id);
$recipients = $node->uid;
echo drupal_get_form('privatemsg_new', $recipients, $subject);
?>

With this snippet you can create a block with containes the send a message form. the recipient field is not heddin yet.
What I'm working right now is showing the real name (which have been set up using realname module) of the author instead of the uid.

I have hide the "To" field with using CSS. I think this is not the right way to do it so please somebody help :)

Am I doing this right?