code: def item_shape!(item_shape)
        @nbuild[NS_EWS_MESSAGES].ItemShape {
          @nbuild.parent.default_namespace = @default_ns
          base_shape!(item_shape[:base_shape])
          mime_content!(item_shape[:include_mime_content]) if item_shape.has_key?(:include_mime_content)
          body_type!(item_shape[:body_type]) if item_shape[:body_type]
          if(item_shape[:additional_properties])
            additional_properties!(item_shape[:additional_properties])
          end
        }
      end
docs: Build the ItemShape element
   @see http://msdn.microsoft.com/en-us/library/aa565261.aspx
   @param [Hash] item_shape The item shape structure to build from
   @todo need fully support all options