Mounting to a ShapeBaseImageData

I am working on a bit in one of my projects where the player can modify their weapon. I would like to be able to mount these new items to the weapon. This would work fine if the weapon was directly a ShapeBase, however using a ShapeBaseImageData I lose access to using ShapeBase's mountObject. Does anyone have any ideas on a better way to go about this idea? Also, I suppose I could have the ShapeBaseImageData inherit mountObject, however I'm not exactly sure on the steps I need to take to go about this.