Sript - trouble with axis.

I have trouble with this script:

 var bullet = Instantiate(Bullet, Spawn.transform.position, transform.rotation);
        bullet.rigidbody.AddForce(Vector3.forward * BulletSpeed);

In unity 3.5 add force at z axis of spawn point. But in new Unity add force at z axis of editor, not spawn point. Why?

try rigidbody.AddRelativeForce (Vector3.forward * BulletSpeed)

Thanks, now work perfect.