How to Create Custom ComboBox using Expression Blend

Question

I am trying to create a custom ComboBox using Expression Blend, not XAML.

I followed the following tutorial:
http://msdn.microsoft.com/en-us/library/ee341409(v=expression.40)

But I couldn't found "ContentPresenter", "ContentPresenterBorder" and"DropDownToggle" in the "Make Into Part of ComboBox".

I actually want to create ComboBox using Grid, TextBlock, ScrollViewer etc like that tutorial rather styling the default ComboBox. Please Help me.

Thanks in advance.