Proxy server

Hi, this is houmi, a novice of Arduino.

Using an Arduino and Ethernet shield, I have tried to run the Arduino program "File->Sketchbook->Examples->Library-Ether->Weclient."

However, because, maybe, our university uses a proxy server through which our PCs and arduinos go to connect to the Internet,
I can not run the program.

Could you please tell me which commands in the Arduino language I should use in order to get to the Internet through a proxy server?