Create a custom instance from icons in RadDiagramToolBox

Question

I'm using RadDiagram for making a designer in our system. I have three parts in my screen, (RadDiagram, RadDiagramToolBox and ToolBar).

What I have to display in my RadDiagramToolBox are icons (images for my custom shapes). For a reason, my custom shapes can not inherit from RadDiagramShape. That's why the RadDiagram didn't accept my custom shapes and I made MyDesigner which is inhering from RadDiagram, and override the this.Drop += MyDesigner_Drop;

To do this I used this hierarchy http://www.telerik.com/forums/raddiagramtoolbox-xaml-example#IUr1zXo3zUq-9NytMbeamw as the following:

<telerik:RadDiagramToolbox Grid.Column="0" Grid.RowSpan="3"
                        Header="{Binding SelectedItem.Header, RelativeSource={RelativeSource Self}}"
                        Visibility="{Binding IsChecked, ElementName=toolboxButton, Converter={StaticResource BooleanToVisibilityConverter}}">
<telerik:RadDiagramToolboxGroup Header=" Charts ">

<telerik:RadDiagramToolboxItem Name="TimeChartIcon" Background="Transparent">
    <telerik:RadDiagramShape Name="TimeChartIcon1" Background="Transparent" BorderBrush="Transparent">
        <Image Source="/Fathom.TestDiagram;component/Images/TimeChartIcon.png"                    
                Stretch="UniformToFill"
                Name="TimeChartIcon2"/>
    </telerik:RadDiagramShape>
</telerik:RadDiagramToolboxItem>

<telerik:RadDiagramToolboxItem Background="Transparent">
    <telerik:RadDiagramShape Name="ValueChartIcon" Background="Transparent" BorderBrush="Transparent">
            <Image Source="/Fathom.TestDiagram;component/Images/ValueChartIcon.png"                    
                    Stretch="Fill"/>
        </telerik:RadDiagramShape>
    </telerik:RadDiagramToolboxItem>
</telerik:RadDiagramToolboxGroup>

<telerik:RadDiagramToolboxGroup Header=" Others "/>
</telerik:RadDiagramToolbox>

and in MyDesigner_Drag I used this http://www.telerik.com/forums/raddiagramtoolbox-drag-drop#trdWTLlUNEKga8H6yFFsqQ and I added these lines of code after Admin Tina's codes:

droppedShape.Background = Brushes.Transparent;                   
droppedShape.Position = e.GetPosition(this);
droppedShape.BorderBrush = Brushes.Transparent;
droppedShape.BorderThickness = new Thickness(2);
droppedShape.Padding = new Thickness(0);
this.Items.Add(droppedShape);

What I got is, I can drag the RadDiagramShape which contains an image from RadDiagrmToolBox and dropped it as a RadDiagramShape contains the same image inside a RadDiagramShape. (How I could have the image in the new dropped instance?)

But What I want is, I want to check inside the MyDesigner_Drag event any info leads me to know the custom shape that the user has dragged and dropped to create an instance from it. Like (Name or Content->Image source) I could see that item.Content is an image but I couldn't access to Name or Image Source and I couldn't see the name or source of the image that I hard-coded in Xaml code in debug mode.