How to run the Windows Store through a proxy internet connection?

My internet runs through a proxy internet connection.It also requires my user name and password.

I am not able to open the windows 8 store(and other apps) even after changing the settings in the command prompt (through the command-"netsh winhttp import proxy source=ie").Internet runs fine in IE10.All apps and the store behave as if the computer is not connected to the internet.

Anybody having any idea what to do?