Why doesn't Hextech Gunblade lifesteal and spell vamp show up in the UI?

Although heals off of all damage, it still effectively includes 15% lifesteal and spell vamp. Why aren't these stats displayed on the character tab in the UI (default C key) under the lifesteal and spell vamp categories? If they were we could also see effective total lifesteal/spell vamp after healing amplification effects such as and Runic Armor.

After the mid year item updates could we get this small change to the UI for clarity?