My mistake. As said you wouldn’t need the category specifier anymore. You wouldn’t need it to be a UPROPERTY either, unless you wanted it to be BlueprintCallable.
Also, are you able to compile without any errors? I was not.
It seems you want to add variables into the UE4 Struct called FRuntimeFloatCurve.
You’d have to make a custom struct with FRuntimeFloatCurve as the base struct in order to do so.
If you haven’t seen this page yet, it should help you a lot.
If you have, then you should be able to declare an instance of your custom struct as a member variable inside of the class that you want to use it in. Then you should declare this member variable as a UPROPERTY with the specifiers that you want. EditAnywhere and giving it a Category should do.
FRuntimeFloatCurve has customization to be drawn in detail panel, for that there is CurveStructCustomization class which you can find in Engine\Source\Editor\DetailCustomizations. To make your FVive3DSPCurveStruct to be drawn also you need to create customization class for your struct.