Rich Metadata

For instance, I would like to expose a DrawingBrush (defined in xaml) as an "Icon" property on the metadata
.  I would like to be able to set the Icon property on the metadata from code-behind.  I have tried the following:
public static readonly DependencyProperty IconProperty = DependencyProperty.Register("Icon", typeof(ImageSource), typeof(DrawingBrush), new PropertyMetadata(null));