Can I use clipping with Unity Sprite in NGUI?

I used NGUI free version (2.7) with Unity 4.3. I have tried to use clipping to restrict the area of viewer by using clipping to hide some content of Unity Sprite. However, it did not work. If it's NGUI own sprite, it worked. Is there a way to use clipping with Unity Sprite? I have done some asset with animation with unity sprite (2D) but it cannot be clipped.