Moving units like in a rts

Hi, I'm just wondering how to do this, I have my mouse picking working but I can't seem to get the movement working properly

runner = new Box("Runner", new Vector3f(), 3, 8, 3);
   runner.setModelBound(new BoundingBox());
   runner.addController(new Controller() {
      private static final long serialVersionUID = 1L;
      public void update(float time) {
          runner.getLocalRotation().mult(Vector3f.UNIT_Z, rDirection);
          Vector3f dir = new Vector3f();

          runner.getLocalTranslation().add(BufferUtils.getVector3Array(pointSelection.getVertexBuffer(0))[0], dir);
          if  (runner.getLocalTranslation().x >= BufferUtils.getVector3Array(pointSelection.getVertexBuffer(0))[0].x){
         if  (runner.getLocalTranslation().z >= BufferUtils.getVector3Array(pointSelection.getVertexBuffer(0))[0].z){
             dir.set(0f, 0f, 0f);
          Vector3f pos = runner.getLocalTranslation();
          float height = terrain.getHeight(pos);
          runner.setLocalTranslation(pos.x, height+8, pos.z);
          System.out.println("Direction : "+dir);

this only works if the runner is at (0,0,0), I just can't seem to figure out how to create a vector between runner.getLocalTranslation and BufferUtils.getVector3Array(pointSelection.getVertexBuffer(0))[0] which is the vector3f of my mousepick.  I feel like I've hit a wall and it's probably something simple, thanks for any help.

I don't know if this is what you need, but here it goes anyway: If you have to vectors A and B (in the same local coordinates), then the vector that goes from A to B is B-A (that is B.subtract(A) )

thanks, that is all I really wanted to know.