Delphi IntraWeb: 2 questions

Hello! This is a question about Delphi 2007 and IntraWeb. I am a Delphi/IntraWeb newbee. I have done lot's of reading of all the available help files, guides and tutorials. I have searched the Internet, but without success to figure out how I can make a standalone app that would present the user with the appropriate form automatically (eather HTML 4.0, WAP or HTML 3.2) depending what browser he uses. Adding the 3 different types of forms to the same project is easy. But, what then? How do you make it serve the right type of form to the right browser/device? Also, because each form will have the same purpose and logic, what would be the best way to avoid code duplication (where to put public procedures). For example, how should I create a function that happens on a button click of each form type (HTML 4.0, WAP or HTML 3.2) and that does something to a ListBox. I can't really pass the names of controls to my function since each form type has a different control type. What can I do to avoid code duplication? Please help, Eugene