The documentation said

http://3cx.org/item/46

My configuration is

<VirtualHost 192.168.1.12>
    RequestHeader set Front-End-Https "On"
    ProxyRequests Off
    ProxyPreserveHost On
    AddDefaultCharset ISO-8859-1
    ProxyPass /exchange http://hera.conama.local/exchange
    ProxyPassReverse /exchange  http://hera.conama.local/exchange
    ProxyPass /exchweb http://hera.conama.local/exchweb/
    ProxyPassReverse /exchweb http://hera.conama.local/exchweb/
    ProxyPass /public http://hera.conama.local/public/
    ProxyPassReverse /public http://hera.conama.local/public/
    ProxyPass /iisadmpwd http://hera.conama.local/iisadmpwd/
    ProxyPassReverse /iisadmpwd http://hera.conama.local/iisadmpwd/
    ServerAdmin psilva@conama.cl
    ServerName correos.conama.cl
    ErrorLog logs/correos.conama.cl-error_log
    CustomLog logs/correos.conama.cl-access_log common
    CacheDisable *
    Options Indexes MultiViews
</VirtualHost>


I get the following errors in apache logs

[Wed Nov 22 09:14:36 2006] [error] [client 10.100.104.100] proxy: error reading status line from remote server hera.conama.local, referer: http://correos.conama.cl/exchange/psilva/?Cmd=navbar
[Wed Nov 22 09:14:36 2006] [error] [client 10.100.104.100] proxy: Error reading from remote server returned by /exchweb/img/task-lg.gif, referer: http://correos.conama.cl/exchange/psilva/?Cmd=navbar
[Wed Nov 22 09:15:21 2006] [error] [client 10.100.104.100] proxy: error reading status line from remote server hera.conama.local, referer: http://correos.conama.cl/exchange/psilva/Inbox/?Cmd=contents
[Wed Nov 22 09:15:21 2006] [error] [client 10.100.104.100] proxy: Error reading from remote server returned by /exchweb/img/dumpster.gif, referer: http://correos.conama.cl/exchange/psilva/Inbox/?Cmd=contents
[Wed Nov 22 09:16:36 2006] [error] [client 10.100.104.100] proxy: error reading status line from remote server hera.conama.local, referer: http://correos.conama.cl/exchange/psilva/Inbox/?Cmd=contents
[Wed Nov 22 09:16:36 2006] [error] [client 10.100.104.100] proxy: Error reading from remote server returned by /exchweb/img/flg-empty.gif, referer: http://correos.conama.cl/exchange/psilva/Inbox/?Cmd=contents