Adding axes to the Unity input manager. As described in the post http://angryant.com/2013/08/04/Unity-Hacks-Dual-sticks/

Controllers.cs

public static void AddAxis (AxisDefinition axis)
{
	if (AxisDefined (axis.name))
	{
		throw new System.ArgumentException (string.Format ("Specified axis \"{0}\" already exists", axis.name));
	}

	SerializedObject serializedObject = new SerializedObject (AssetDatabase.LoadAllAssetsAtPath ("ProjectSettings/InputManager.asset")[0]);
	SerializedProperty axesProperty = serializedObject.FindProperty ("m_Axes");

	axesProperty.arraySize++;
	serializedObject.ApplyModifiedProperties ();

	SerializedProperty axisProperty = axesProperty.GetArrayElementAtIndex (axesProperty.arraySize - 1);

	GetChildProperty (axisProperty, "m_Name").stringValue = axis.name;
	GetChildProperty (axisProperty, "descriptiveName").stringValue = axis.descriptiveName;
	GetChildProperty (axisProperty, "descriptiveNegativeName").stringValue = axis.descriptiveNegativeName;
	GetChildProperty (axisProperty, "negativeButton").stringValue = axis.negativeButton;
	GetChildProperty (axisProperty, "positiveButton").stringValue = axis.positiveButton;
	GetChildProperty (axisProperty, "altNegativeButton").stringValue = axis.altNegativeButton;
	GetChildProperty (axisProperty, "altPositiveButton").stringValue = axis.altPositiveButton;
	GetChildProperty (axisProperty, "gravity").floatValue = axis.gravity;
	GetChildProperty (axisProperty, "dead").floatValue = axis.dead;
	GetChildProperty (axisProperty, "sensitivity").floatValue = axis.sensitivity;
	GetChildProperty (axisProperty, "snap").boolValue = axis.snap;
	GetChildProperty (axisProperty, "invert").boolValue = axis.invert;
	GetChildProperty (axisProperty, "type").intValue = (int)axis.type;
	GetChildProperty (axisProperty, "axis").intValue = axis.axis - 1;
	GetChildProperty (axisProperty, "joyNum").intValue = axis.joyNum;

	serializedObject.ApplyModifiedProperties ();
}


public static SerializedProperty GetChildProperty (SerializedProperty parent, string name)
{
	SerializedProperty child = parent.Copy ();
	child.Next (true);

	do
	{
		if (child.name == name)
		{
			return child;
		}
	}
	while (child.Next (false));

	return null;
}