How do you use iTween with multiple states and easing?

I am animating a menu using buttons tracked to empty GOs for a exploded menu (I did that to animate in one direction and set rotation on the GO without rotating the buttons). Each of those empty GOs are animated by a MenuScript.cs which moves the button to a location and has some setters that are called by behavior scripts at different states.

So for example: when the state "Enter" is triggered, the behavior script calls MenuScript.SetEnter() and movement is handled inside of Update. Then it moves to a position and then the state gets switched to Normal.

I am currently using Vector3.Lerp() but I would love to use iTween for some awesome easing. However, it seems the easing is only available in MoveTo() which I've only seen examples in the Start() function, how do I get a GO to move to different locations after Start() has completed?