C# 2010 designer

Question

I am working with a C#.net web forms 2010 application that I am going to be adding some web forms to the entire application. I am asking the following question since I have C#.net expereince working with desktop applications.
When debugging a desktop application, I can 'step into the code' for a designer. (This may be allowed since the code generated by the designer is C# code.)

Thus, I would like to know if I can 'step into' the code generated by the asp.net designer. This code ends up being html. If this is possible, can you tell me how to step into this html that the desginer setup and/or point me to reference on how to debug the html (designer code)?

Also can you debug xml (like the web config file)? If so,would you point me to a reference i can use for debugging xml?