From Cedric Pinson, "Here a patch to be able to clone stateattribute, in order to do that i

moved the StateAttribute::Callback structure to a file
StateAttributeCallback with the same behavior as NodeCallback.
"

include/osgAnimation/UpdateCallback

@@ -36,8 +36,6 @@ namespace osgAnimation
         virtual int link(osgAnimation::Animation* animation) = 0;
         virtual void updateLink() = 0;
         virtual const std::string& getName() const = 0;
-
-        virtual ~AnimationUpdateCallbackBase() {}
     };
 
     template <class T>
@@ -130,7 +128,7 @@ namespace osgAnimation
 
 
 
-    class OSGANIMATION_EXPORT UpdateMaterial : public AnimationUpdateCallback<osg::StateAttribute::Callback>
+    class OSGANIMATION_EXPORT UpdateMaterial : public AnimationUpdateCallback<osg::StateAttributeCallback>
     {
     protected:
         osg::ref_ptr<osgAnimation::Vec4Target> _diffuse;
@@ -147,6 +145,7 @@ namespace osgAnimation
         void update(osg::Material& material);
         bool needLink() const;
         bool link(osgAnimation::Channel* channel);
+        osgAnimation::Vec4Target* getDiffuse();
     };
 
 }