如何在Visual Studio 2012终极版本中自动测试Web性能和负载测试项目

I am using VS2012 Ultimate to creating Web performance test and Load test project.First I created sample web page application, in this web page two text box username and password and submit button.Then run the web test project, it build successful and click the add recording, automatically opened internet explorer then we enter the web application url manually and enter the username, password and submit. Then stop the recording, it will go to the project and processing, finally result is passed.But I want when i run the web performance and Load test project and give only url then automatically enter username and password and submit. Please guide me.I am using VS2012 Ultimate to creating Web perf