[exim] Outlook problem

Hello List:

I'm using the following ACL to drop incorrect HELO names:

    deny condition = ${if ! match {$sender_helo_name}{\N^[^.].*\.[^.]+$\N}}
           message = "See RFC2821 section 4.1.2 for legal domain syntax"
       log_message = invalid HELO syntax 1 $sender_helo_name

The problem is that Outlook (On XP Pro) sends computer name as host
name and the connection gets dropped.

2008-01-12 08:45:21 H=(GEORGE) [68.183.245.148] rejected EHLO or HELO
george: invalid HELO syntax 1 GEORGE


Is there something that can be done to be able preserve the use of
the ACL. Maybe there is a setting on the XP that is incorrect? This
doesn't happen with Thunderbird, but I cannot tell all clients not
use MS crap.

George