Even if the scaler could do that (although it might be technically possible, but not allow it because...), there's no way to get it out the back end. HDMI doesn't currently provide a way to transport 4K60.
Bottom line. 4K is a developing standard with only academic usefulness right now. There's no [meaningful] content, limited transport, and support in existing devices is mostly for marketing purposes. Don't buy anything [for] 4K that doesn't support HDMI 2.0.