i think no,because i found at interface changing only the change of a text "missed" (Evade sckill) . You may craft it by yourself at trigger way (as 1 of various variants)
u will have to create a floating text to indicate it.
Floating Text - Create floating text that reads Backstab at (Position of (Triggering unit)) with Z offset 90.00, using font size 10.00, color (100.00%, 0.00%, 0.00%), and 0.00% transparency
Floating Text - Set the velocity of (Last created floating text) to 64.00 towards 90.00 degrees
Floating Text - Change the lifespan of (Last created floating text) to 3.00
Floating Text - Change the fadepoint of (Last created floating text) to 2.00