create child node from parent node page.

The Idea: to have form for add child node right on parent node page. Exactly as this forum have when you are logged.
The way I try to go this: add to parent node CCK Computer Field with code:

$pid = 254; // - ID of current node
$type = 'my_content_type';
global $user;
$nnode->uid = $user->uid;
$nnode->name = $user->name;
$nnode->type = $type;
$nnode->created = time();
$nnode->parent_node = $pid;
$nnode->taxonomy[12] = array('tid' => '12', 'vid' => '4', 'name' => 'news', 'description' =>'' , 'weight' => '0');

require_once(drupal_get_path('module', 'node') . '/node.pages.inc');
$form = drupal_get_form($type .'_node_form', $nnode);
$display = $form;

Everything looks cool, you can fill fields, press save and new node of 'my_content_type' will be created, but... no relationship.

Traditional "http://mysite/node/add/my_content_type/parent/254" works fine...

Any suggestions ?
Thank you!