Through the Accessible View – received via the top window – I didn't find a way to get the original model element. 
For example:
When I walk through the accessible tree of an AccessibleDrawDocumentView I only get access to XAccessibleContext (e.g. AccessibleShape) objects and not to the original UNO (e.g. XShape) for modify or manipulate it. In the AccessibleShape.cxx a function for returning the original UNO element already exists (uno::Reference< drawing::XShape > AccessibleShape::GetXShape()) but is protected via its access modifier. I would recommend that it should be possible to receive the original UNO and even the Model through an interface e.g. the XAccessibleContext interface. In the XAccessibleContext interface description is declared "… On the other hand it gives access to objects that expose the represented content. …".

I'm searching for a long time for a way to bring the XAccessible in relation to its UNO element and Model.