Validate form with default values?

[eluser]Sven Delle[/eluser]
So I:

1: Installed a clean CI 2.1.0.
2: Downloaded and implemented HMVC according to wiki.
3: Extended Form_validation class according to wiki.
4: Went through the Form Validation Tutorial, step by step.

Result: Absolutely NO callbacks!

What am I doing wrong - I assume I'm doing SOMETHING wrong - otherwise HMVC DO NOT WORK WITH callbacks!

This is my Controller:

Code:

<?php
class Admin extends CI_Controller
{
public function __construct()
{
  parent::__construct();
  $this->load->library('form_validation');
  $this->form_validation->CI =& $this;
}

public function index()
{  
  $this->load->view('login_form');
}

public function validate_user()
{
  $this->load->helper(array('form', 'url'));
  
  $this->form_validation->set_rules('username', 'Username', 'required', 'callback_username_check');
  $this->form_validation->set_rules('password', 'Password', 'required');
  $this->form_validation->set_rules('passconf', 'Password Confirmation', 'required');
  $this->form_validation->set_rules('email', 'Email', 'required');

  if($this->form_validation->run() === FALSE)
  {
   $this->load->view('login_form');
  }
  else
  {
   $this->load->view('dashboard');
  }
}

public function username_check($str)
{
  echo 'Hello World!'; // This NEVER gets called!!!
  
  if ($str == 'test')
  {
   $this->form_validation->set_message('username_check', 'The %s field can not be the word "test"');
   return FALSE; // I've tried with "AAAAARGH!"
  }
  else
  {
   return TRUE; // I've also tried this with "AAAAARGH!"
  }
}
}

Someone please help me, as I'm in the middle of the night. A was supposed to get things done - not trying to fix things.