Hey Caesar,
Agnostic of the whole mouse-input concept, think about how you'd trigger an event with a changing float. You may have done it before. For example, detect when the float variable stops changing, or when it's <X (where X is a value you determine).
So, something like a Float Compare action that determines if the variable is between -1 - 1, or a boolean in a separate FSM that changes its value if the mousewheel Float variable is !=0.
Just a couple ideas. Hope you figure it out!
I am using GetAxis with "Mouse ScrollWheel" as the Axis Name, but how do I use the value stored in the variable? If "Every Frame" is checked, it never fires a finish event.