Description:
------------
I submit an attachment and then send via XML inside a node. When I 
attach a file larger than 12k this function creates an empty node with 
no evident error report on php.
(This is only a sample of the real code)

Reproduce code:
---------------
function creaElem($name, $value="", $parent=null) 
{
    $el=$this->Document->createElement($name);
  if ($value!="")
      $el->appendChild($this->Document->createTextNode($value));
    if ($parent!=null)
      $parent->appendChild($el);
    return $el;
}
function AttachFile($parentnode,$attachmentname)
{
\\
$packet->creaElem("nomefile",$attachmentname,$parentnode);
$newnode=$packet->creaElem("attach","",$parentnode);
$whatsinside=file_get_contents ($_FILES['attachment']['tmp_name']);		
$cdata=$this->Document->createCDATASection(base64_encode($whatsinside));		$newnode->appendChild($cdata);
}


Expected result:
----------------
When I run AttachFile(..) and My attachment size is larger than 12k this 
function creates an empty node. With attachments<12k it works.
Any suggestion?
Thanks in advance