Description:
------------
test System: 
Windows 7 XAMPP 1.8.1 php Version 5.4.7.
Linux Php Version 5.3.24

Using imap_headerinfo() returns data without return_pathaddress. On the mail 
Server the Mail Header are complete and on my local Server i'm using Thunderbird 
and there are also existing return_pathadress.

Test script:
---------------
$account["webmail"] = array("info@xxx.com","xxx"); 
$imap["webmail"] = "{mail.xxx.com:143/imap/novalidate-cert}INBOX"; 
... 
$ident = "webmail"; 
$get = imap_open($imap[$ident], $account[$ident][0], $account[$ident][1]); 
$array_mail_actual_UID = imap_sort($get,SORTARRIVAL,0,SE_UID); 
$UID_number = ""; 
foreach($array_mail_actual_UID AS $number_of_mail){ 
  $UID_number = $number_of_mail; 
  $number_of_mail = imap_msgno($get,$number_of_mail); 
  $header[] = imap_headerinfo($get, $number_of_mail);  
} 
imap_close($get);  
echo "<br><pre>"; 
print_r($header); 
echo "</pre><br>";

Expected result:
----------------
the print_r of return_pathaddress

Actual result:
--------------
print_r() returns data, bud incomplete without return_pathaddress