The web.requestContent method you've used here is for calling the url/posting the data and not for authentication.
HTTP Authentication does not come standard in the BrowserField2 API. You'll have to implement ProtocolHandler and override it for doing authentication.
Check this :
http://208.74.204.192/t5/Java-Development/How-to-enable-HTTP-Authentication-in-your-BrowserField2/ta-p/623025
This will help you implement that.