Top Down C++ Template Adjust Camera Distance in BP

I just started using the top down C++ template. In MyCharacter.cpp if I change the CameraBoom->TargetArmLength value then the camera distance is adjusted as expected.

However when I create a blueprint based off the MyCharacter class and modify the CarmeraBoom component’s “Target Arm Length” variable, it does not modify the distance.

How would I go about doing this in the Blueprint?