Proxy Change With Webbrowser Control

We are in need of a function that allows proxies switching with username/password basic Authorization. This must allow a webbrowser control use this proxy with basic Authorization. We must be able to use this proxy continuously. We need to change the proxy then load a page in a webbrowser control then be able click a link/button in this control. Requirement. MUST BE WRITTEN IN VB.NET{no exceptions) The .NET version is 3.5 Must be able to change the proxy on the fly must be able to change the Authorization information on the fly must be able to click a link/button in a webbrowser control using the proxy.