Nothing refers to UI element from ref doc
http://msdn.microsoft.com/en-us/library/da0adyye.aspx
Even looking at some example here http://vishalnayan.wordpress.com/2011/03/22/creating-credential-store-for-form-authentication-in-asp-net-3-5/
I don’t understand how username and password in webconfig credential are mapped with UI elements.
In the example the textbox has id UsernameText and not Username so how can asp.net could do the mapping between the two ?
It doesn’t map to UI elements automatically. After the user enters his username and password it is being checked in code-behind like that: