Exposing "Shift Child At" function to Blueprint (4-27)

Hello, I am currently working on some widgets which would require to update a container’s children order, for which I would love to use the “Shift Child At” function. unfortunately I am kind of a real beginner at this, I don’t know how I could simply make this function “BlueprintCallable” so I can use it.
A lot of functions are available but not exposed to bluebrint so I’d like to know how I could expose them to blueprint.

Thank you for your help :slight_smile:

P.S. : It’s on a C++ Project on a Built from source version of the engine, if this intel can help