Access prefab's variables after instantiation

I have looked at similar questions: http://answers.unity3d.com/questions/33433/Cant-access-prefabs-variables-once-instantiated.html and http://forum.unity3d.com/threads/134864-accessing-an-instantiated-prefab-s-variables but they do not solve my problem.

Say, I have a prefab called MovingSoldier and I instantiate it as follows:

GameObject ms=(GameObject) Instantiate(MovingSoldier,new Vector3(10,32,91),transform.rotation);

MovingSoldier has a C# script attached called SoldierScript and the script has a variable speed. How do I access and change the variable speed from the object ms I created above?

you can try sendmessage Unity - Scripting API: GameObject.SendMessage
it’s okay to send information every few frames and if you need something faster, you need to write the code in your script that gets the variable change signal from the other script it depends on, and look for questions called how to access variable from other script