reverse proxy POST method problem

[redwood]

I'm trying to setup a reverse proxy following the guide
http://www.apachetutor.org/admin/reverseproxies


I have a private appserver: http://internal.example.com
which I wish to access through a reverse proxy from
the public webserver http://www.example.com

#/etc/apache2/vhosts.d/99_myproxy.conf
ProxyRequests off
ProxyPass /app/ http://internal.example.com/
ProxyHTMLURLMap http://internal.example.com http://www.example.com:8080/app
ProxyHTMLURLMap https://internal.example.com https://www.example.com/app

<Location /app/>
ProxyPassReverse /
SetOutputFilter proxy-html
ProxyHTMLURLMap / /app/
ProxyHTMLURLMap /app /app
RequestHeader unset Accept-Encoding
</Location>


My problem is that the webapp has a User:Pass login screen
using the POST method.
When I connect to http://www.example.com/app/
I get properly redirected to the login screen
https://www.example.com/app/cgi-bin/app/app_login

After entering my Username:Password, however, I just get a timeout.

When I monitory the http headers using Firefox's LiveHTTPHeaders addon
I see the following:

POST /app/cgi-bin/app/app_login HTTP/1.1

Host: www.example.com
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9b5) Gecko/2008032619 Firefox/3.0b5

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip,deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Keep-Alive: 300

Connection: keep-alive

Referer: https://www.example.com/app/cgi-bin/app/app_login

Cookie: kt_language=en; PHPSESSID=4c44842ce...
Content-Type: application/x-www-form-urlencoded

Content-Length: 79

OP=LOGIN&SN=app.example.com&UI=user&PW=password&MO=BROWSE&LOGIN=+LOG+IN+


I think the POST / Host is wrong.
I think they should be
POST: /cgi-bin/app/app_login HTTP/1.1
Host: internal.example.com (or maybe www.example.com/app)


Any ideas on what I'm doing wrong?
Thanks.

[richard.scott]

Is that howto valid for this version of Apache?

I just use this in my virtual host config: