Need to extend existing windows form controls

Question

I have a windows form project and want to extend current windows form controls (checkbox, radio button, and textbox) with custom properties. 

First of all is that possible?  It seems so, but i'm not 100% on how to properly do that...

I have started to build a second project in my solution which is a DLL project and create custom classes that inherit from the checkbox, radio button and textbox classes.  I made a reference to the dll project in my main project, however those controls do not show up in my toolbox when trying to add them to a windows form.

How do i get it where the controls are usable from the toolbox in my windows form project.