I'm trying to make simple use of the DataObjectManager, I need Date, Title, and a PDF file upload. I've got it working apart from everytime I save, it doesn't save the date, only the title. This is my code...

PdfFile.php:

<?php

class PdfFile extends DataObject
{
   static $db = array (
      'Date' => 'Date',
      'Title' => 'Text'
   );

   static $has_one = array (
      'PDF' => 'File',
      'FilePage' => 'FilePage'
   );

   public function getCMSFields_forPopup()
   {
$dateField = new DateField('Date');
$dateField->setConfig('showcalendar', true);
      return new FieldSet(
         $dateField,
         new TextField('Title'),
         new FileField('PDF')
      );
   }
}

?>

FilePage.php:

<?php

class FilePage extends Page
{
static $db = array (
);

static $has_one = array (
);

static $has_many = array (
'PdfFiles' => 'PdfFile'
);

public function getCMSFields()
{
$f = parent::getCMSFields();
$f->addFieldToTab("Root.Content.PDF", new DataObjectManager(
$this,
'PdfFiles',
'PdfFile',
array('Date'=>'Date', 'Title'=>'Title'),
'getCMSFields_forPopup'
));

return $f;
}
}

class FilePage_Controller extends Page_Controller {
}

?>

Any advice would be much appreciated!

Many thanks,
Vic