从pop3服务器获取邮件，并在邮件服务器中保留副本

我使用以下代码从我们的POP3邮件服务器获取邮件。我已经成功取回邮件。我想在服务器上留下邮件的副本。我该怎么做呢

    <?php
    /* connect to gmail */
    $hostname='{mail.xxx.com:110/pop3}INBOX';
    $username='yyy.xxx@xxx.com';
    $password='xxx_9851';

    /* try to connect */
           $inbox = imap_open($hostname,$username,$password) or die('Cannot connect to Gmail: ' . imap_last_error());
    echo "here";
    /* grab emails */
    $emails = imap_search($inbox,'SUBJECT "hi"');/* if emails are returned, cycle through each... */
    //print_r($emails);
    if($emails) {
      /* begin output var */
      $output = '';
      /* put the newest emails on top */
      rsort($emails);
      /* for every email... */
      foreach($emails as $email_number) {
        /* get information
 specific to this email */
    $overview = imap_fetch_overview($inbox,$email_number,0);
    echo "<pre>";
//  print_r($overview);
    $message = imap_fetchbody($inbox,$email_number,2);
    $header=imap_fetchheader($inbox,$email_number);
//print_r($message);
//print_r($header);
    /* output the email header information */
    $output.= '<div class="toggler '.($overview[0]->seen ? 'read' : 'unread').'">';
    $output.= '<span class="subject">'.$overview[0]->subject.'</span> ';
    $output.= '<span class="from">'.$overview[0]->from.'</span>';
    $output.= '<span class="date">on '.$overview[0]->date.'</span>';
    $output.= '</div>';
    /* output the email body */
    $output.= '<div class="body">'.$message.'</div>';
     $s = imap_fetchstructure($inbox,$email_number);
    // print_r ($s->parts);
        if (!$s->parts) 
        {// simple
       // getpart($inbox,$email_number,$s,0);  // pass 0 as part-number
        }
        else {  // multipart: cycle through each part
        foreach ($s->parts as $partno0=>$p){
          attachment_to_file($inbox,$email_number,$p,$partno0+1);
        }
        }
  }

非常感谢任何帮助。谢谢你