SSL'd Apache 2.2 Reverse Proxy to OWA 2007 Upload Problem

Hello All,

We have Apache 2.2.6 successfully doing reverse proxying for OWA 2007,
but we have a problem. When trying to upload files greater than about
100kb in size to attach to emails, after the upload completes, the
page refreshes to a blank page.

When the user opens the saved draft up after getting back to the OWA
interface, there is no attachment in the draft email.

This problem occurs with Firefox, IE6 and IE7. I'm hoping someone out
there has tackled and solved this particular problem. I've been
beating my brains out trying to find a solution to it.

Our environment is as follows:

Client <--(HTTPS)--> Firewall <--> Apache2 <--> Firewall <--(HTTPS)--
>Exchange

In case the problem might be in our conf, here it is:

<VirtualHost aaa.bbb.ccc.ddd:443>

DocumentRoot "/srv/httpd/htdocs"
ServerAlias exmail.domain.com:443
ServerName mxa.domain.com:443
ServerAdmin postmaster.DeleteThis@domain.com
ErrorLog /var/log/httpd/error_log
TransferLog /var/log/httpd/access_log
CacheDisable *

SSLEngine on

SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:
+SSLv2:+EXP:+eNULL
SSLCertificateFile /etc/httpd/cert.pem
SSLCertificateKeyFile /etc/httpd/key.pem

<FilesMatch "\.(cgi|shtml|phtml|php)$">
SSLOptions +StdEnvVars
</FilesMatch>
<Directory "/srv/httpd/cgi-bin">
SSLOptions +StdEnvVars
</Directory>

BrowserMatch ".*MSIE.*" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0

CustomLog /var/log/httpd/ssl_request_log \
"%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"

RequestHeader set Front-End-Https "On"

ProxyRequests Off
SSLProxyEngine On
SSLProxyVerify none
SSLProxyMachineCertificateFile /etc/httpd/proxy.pem
ProxyPreserveHost On

AddDefaultCharset UTF-8
RequestHeader unset accept-encoding

RewriteEngine on
RewriteRule ^/$ /exchange/ [R]
RewriteRule exchange([^/].*) /exchange/$1 [R,QSA,L]
RewriteRule exchweb([^/].*) /exchweb/$1 [R,QSA,L]

<Location /exchange>
ProxyPass https://10.100.0.14/exchange
ProxyPassReverse https://10.100.0.14/exchange
SSLRequireSSL
</Location>
<Location /exchweb>
ProxyPass https://10.100.0.14/exchweb
ProxyPassReverse https://10.100.0.14/exchweb
SSLRequireSSL
</Location>
<Location /public>
ProxyPass https://10.100.0.14/public
ProxyPassReverse https://10.100.0.14/public
SSLRequireSSL
</Location>
<Location />
ProxyPass https://10.100.0.14/
ProxyPassReverse https://10.100.0.14/
SSLRequireSSL
</Location>
<Location /iisadmpwd>
ProxyPass https://10.100.0.14/iisadmpwd
ProxyPassReverse https://10.100.0.14/iisadmpwd
SSLRequireSSL
</Location>

</VirtualHost>