[CentOS] Apache reverse proxy authentication problem on RHEL based distribs only

Hi,

I'm currently setting up an Apache SSL reverse proxy for Exchange 2003 
Outlook Web Access. The setup that I have works fine on my Gentoo laptop 
or on a Trustix server, however, when I try to set it up on an RHEL 
based distro, with the exact same virtual host settings, I get some 
weird error with the authentication mechanism. I have tried with both 
CentOS 4.2, based off the server CD and Whitebox 4 and I get the same 
result.

We did a network trace off the Exchange server, and noticed we noticed 
what is the problem, but can't figure out why only the configuration 
from those distros are causing it. When getting the HTTP authentication 
prompt from the Apache front-end, I enter "domain\user" for the user, 
but the Apache front-end only sends back part of the authentication 
string to the exchange. As an example, "domain\user" would only send 
back "d\u" to the Exchange server. This does not happen at all with the 
other distributions, as I get the full "domain\user" string sent back to 
the Exchange.

Does anyone have any idea as to what could be causing this, and how I 
might go about fixing it? All our environment consists of the same 
distribution and I would prefer not to introduce a different one just 
for this purpose.

Here is my virtual host configuration for this:

==================================
<VirtualHost xxx.xxx.xxx.xxx:443>

   ServerName testproxy.domain.com

   SSLEngine On
   SSLCertificateFile /etc/httpd/conf/ssl.crt/server.crt
   SSLCertificateKeyFile /etc/httpd/conf/ssl.key/server.key

   RequestHeader set Front-End-Https "On"

   ProxyRequests Off
   ProxyPreserveHost On

   LogLevel debug

   <Location /exchange>
     ProxyPass http://yyy.yyy.yyy.yyy/exchange
     ProxyPassReverse http://yyy.yyy.yyy.yyy/exchange
     SSLRequireSSL
   </Location>

   <Location /exchweb>
     ProxyPass http://yyy.yyy.yyy.yyy/exchweb
     ProxyPassReverse http://yyy.yyy.yyy.yyy/exchweb
     SSLRequireSSL
   </Location>

   <Location /public>
     ProxyPass http://yyy.yyy.yyy.yyy/public
     ProxyPassReverse http://yyy.yyy.yyy.yyy/public
     SSLRequireSSL
   </Location>
</VirtualHost>
==================================

Any information will be appreciated.

Thanks,
Steve Johnson