IIS 7.5 ReverseProxyInboundRule troubleshooting or redirection problem

Hi
We have a inbound rule with the following:
Matches the pattern: (.*)
Using: Regular Expressions
No conditions
No Server variables
Action: Action type: Rewrite
Action Proporties: Rewrite URL: http://our internal IP addres/{R:1}
Append query string is selected
Stop processing of subsequent rules is selected
Our users are connecting to the above webproxy IIS and are being redirected to above mentioned 'URL:http://our internal IP addres/{R:1}'  just fine, but when a user is clicking on a link on the redirected website, things go wrong.
Our users are using a package tracking system, which make an inquiry to a dhl.com website, and then they are supposed to go back to our 'URL:http://our internal IP addres/{R:1}' with requested result from dhl.com.
But i simply cannot see how to configure that with URL rewrite. Can anyone direct me in the correct direction of how to do this?