Here’s my last try. This gives your actor a node that is the same as AddBoxCollision. To the best of my abilities, I think that is what you’re asking. Otherwise, good luck. I did my best to understand.
In your class declaration, add:
UFUNCTION(BlueprintCallable, Category = "MyBoxCollision")
AActor* MyAddBoxCollision(bool ManualAttachment, FTransform RelativeTransform, FName TemplateName);
In your cpp file for the class add:
AActor* MyClass::MyAddBoxCollision(bool ManualAttachment, FTransform RelativeTransform, FName TemplateName)
{
return NULL; // replace this with the box creation code
}