Getting SSRS to work with ARR (Application Request Routing) URL Rewrite

I found an interesting article about setting up a reverse proxy in IIS 7 and ARR. I would like to use one external IP and route the user to multiple internal Report Servers:

http://blogs.msdn.com/b/carlosag/archive/2010/04/02/setting-up-a-reverse-proxy-using-iis-url-rewrite-and-arr.aspx

My normal .asp pages are displayed using the proxy, but I have not been able to get my SSRS 2008 reports to show up. I can get to the list viahttp://<some_proxy_server>/ReportServer/Reports

However, except for some menu items, the report data is not displayed. Has anyone successfully gotten SSRS to work using ARR and URL ReWrite? Thanks.