I have installed geoserver 2.5 with integrated GWC on a windows server 2008 R2 in tomcat6. I am not able to create map caches with GWC. GWC gives me "404: cannot communicate with server. I have a reverse proxy set up and a url rewrite in IIS to provide internet access. What do I have to do to establish communication again between Geoserver and GWC?