Nginx reverse proxy on another web server with redirection

[fijfajfu]

Hi all,
I have the problem with configuring nginx to perform proxy redirection to
web server that appends some its local path to redirected address. As a
result I get url of my server (where nginx is running) but with path (from
another machine) appended. 

The configuration is:
       location ~* ^/3rdparty/(.*)___(.*)___(.*)___(.*)$ {
                proxy_pass https://$1.$2.$3.$4?$args;
                proxy_redirect     off;
                proxy_set_header   Host $http_host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For
$proxy_add_x_forwarded_for;
        }

When I type this:
http:// 192.168.237.208/3rdparty/192___168___237___222
I would expect content from here:
https://192.168.237.222
but I get attempt from server to get content from here - which doesn't
exist:
http://192.168.237.208/3rdparty/192___168___237___222/users/sign_in

How to remove /users/sign_in sufix but to process that within nginx server?

When I go directly to target server typing this:
https://192.168.237.222
I get redirected to 
https://192.168.237.222/users/sign_in which brings the right content.

Thank you in advance for you comments/help!

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,249291,249291#msg-249291