UserControl with a collection property accesible in the designer

Question

How do I make a collection property in my UserControl accesible in the designer? When in design time, I want to provide strings to my control being dragged onto my form. When I click the property, a collection input form appears, but it won't accept any input. Do I need an attribute declaring how the designer should interpret my property? If yes - how? Anyone - thanks. Nikolaj