How to make a GdkPixbuf include obscuring windows?

[Ken Siersma <siersmak ekkinc com>]

I have an application which has a GtkDrawingArea.  I am currently taking 
pictures (screenshots) of the GtkDrawingArea using 
gdk_pixbuf_get_from_drawable and saving the GdkPixbuf to an image file.  
This works fine when there are no windows obscuring the GtkDrawingArea, 
but sometimes I'd like to be able to include widgets that are children 
of the toplevel in the GdkPixbuf.  Is there anyway to do this using just 
GTK? 

Thanks,
Ken