// http://tools.ietf.org/html/rfc3501
                function _imap_append($mailbox, $uid, $message, $flags, $internal_date)
                {
                        if($this->put_line($this->tag . " APPEND $mailbox $flags $internal_date {".$uid."}" ))
                        {

                                $response_append=$this->get_server_responce();
                                if($response_append != '+ Ready for literal data')
                                {
                                        $this->error= "Error : $response_append !<br>";
                                        return false;
                                }
                        }
                        else
                        {
                                $this->error= "Error : Could not send User request. <br>";
                                return false;
                        }

                        if($this->put_line($message))
                        {
                                $response_sub=$this->get_server_responce();
                                
                                if(substr($response_sub,strpos($response_sub,"$this->tag ")+strlen($this->tag)+1,2)!="OK")
                                {       
                                        $this->error= "Error : $response !<br>";
                                        return false;
                                }
                        }
                        else
                        {
                                $this->error= "Error : Could not send User request. <br>";
                                return false;
                        }

                        return true;
                }