First Person Controler and Water wont effect gravity

I’m using the standard asset First Person Controller. I set up some water and made the water a cube and made that collider a trigger. I want to make it so when the character falls down into the water there is no gravity so he can start swimming. But when I use

`void OnTriggerEnter(Collider other)
{
other.attachedRigidbody.useGravity = false;

}

`nothing happens, the gravity doesn’t stop but if i do just

OnTriggerEnter(Collider other)
{
    Destroy(GameObject);

}

then when the character hits the water it works and he gets deleted. So I don’t know why the gravity wont turn off in the first example. The only thing I can think of is all the scripts on the First Person Controller are in Java, and my scrips are in C#. Are java and C# compatible together in unity?

attach this to object with trigger that simulates water. on enter to trigger character controller’s speed is set to zero and gravity is disabled. on exit gravity is enabled again.

using UnityEngine;
using System.Collections;

public class WaterZone : MonoBehaviour
{
	void OnTriggerEnter(Collider other)
	{
		CharacterMotor cm = other.gameObject.GetComponent();
		cm.SetVelocity(Vector3.zero);
		cm.movement.gravity = 0f;
	}
	void OnTriggerExit(Collider other)
	{
		CharacterMotor cm = other.gameObject.GetComponent();
		cm.movement.gravity = 10f;
	}
}