I have created a composite chart with n number of stackcolumnchart layers, each layer having x number of series in it.  Each layer also has its own X-axis and the axes are all offset by a certain margin to the left and the right so my chart primitives do not overlap.  In the past, when I have drawn primitives on a chart I have used the Grid.X and Grid.Y properties of the FillSceneGraphEventArgs delegate to map coordinates to the X and Y axes.  However, in this case, those properties are not set and I am thus unable to map x and y coordinates on this basis.

How do I go about drawing primitives on this chart using the fillscenegraph event?  Or is there another event I should use or another method to map x and y coordinates so I can position and draw my primitives correctly on the sheet?  Help here would be much appreciated, if this is not possible to accomplish there is not much reason for me to move forward with this particular chart.