I have a small webapp running on Windows server 2008 R2 and Tomcat 7.0. Also use the Tomcat service configuration/monitor utility to manage the webapp. 
At the moment the service is behind an http proxy, and need to communicate with a webpage outside. I tried setting -Dhttp.proxyHost=<server> and -Dhttp.proxyPort=<port> against Java options in the configuration tool.  Also tried setting the flags in conf/catalina.properties but still doesn't help.. What could I be doing wrong ? Does it have anything to do with the Windows proxy settings ?
This problem has been asked and answered several times, but none of the solutions seem to work for me.
EDIT: I tried all possibilities, Java Configuration, Internet explorer settings and the jvm flags as said in the question. None of them works.