Animation Curves applied to scale in Unity 3.5.7f

Hi,

I need to create an animation curve for a tween with Hotween. I have been checking the creation of animation curves in 3.5.7f and there's something I do not understand. From the docs I can see how 3 different timeline curves can be applied. One for x, other for y and another for z. With the current system this seems that can't be done and I can only create an AnimationCurve that will have as output just a float? Am I missing something? How can be this applied to a vector3 like the scale? Any help would be apreacciated.

Thanks in advance.