There are 6 different header options that can be set.  Perhaps
one of the other 4 might allow this user to reply successfully?
 
<abstracted>
Options for mail headers of incoming postings (choose one):
             FULLhdr or FULLBsmtp              -> "Full" mail headers
             IETFhdr                           -> Internet-style headers
             SHORThdr or SHORTBsmtp            -> Short (default) headers
             DUALhdr                           -> Dual headers, useful with PC
                                                  or Mac mail programs
 
/Pete