extending ASP.NET 2.0 controls

Question

Dear All,

I want to create a new custom web control by extending the 1)HTMLInputFile control and 2)File Upload control
The purpose of extending the control is to add the following functionalities
not provided by the controls:

a.Selection of Folders
b.Retrieval of the folder path

Can someone tell me the proper way of doing it,so that I can drag it from the toolbox and us it.
I shall be grateful for this help.

Thanks in advance for your time and effort.