Easiest way to visually design a "usercontrol" (interactive designer)

Ok,

I create a new project of control library type etc, create a new scene
and design a couple rectangles etc. A fill of one of htose rectangles
I'd liek to expose as a control property.

I can build the project just fine, but when I add reference then try to
add the control from the library, it doesnt appear until I extend
"control" or "usercontrol" or "UIElement" etc... in which it shows up in
the library, but doesnt display anything.

Is there any easy way to simulate the functionality of flashes MC's?
Where I'd create a basic movieclip with its own code, then its in the
library and I can simply drag it out onto a scene?

Thanks in advance
Weston Weems