How to insert first blank row to binded ComboBox?

Question

Hello, I'm working on Winform application, where i have a ComboBox who is binded to some DataSet. Now, i want a black first row in the combox (which the user will use as "I dont want to select anything!" item). how can i do it? I tried to use the Add method of the ComboBox.Items, and it works fine but in the top of the combobox, and not in the head of it (the last item, not the first one). Thanks alot, Liran.