Find where the animation is handled for modern magics.. you'll see something that says send animation and send gfx with some ID's. All you need to do is change those ID's to the animation and GFX ID's of your choice. I'll update this with where to go to find this in an hour.
MagicConstants.java line 66 and 68
Code:
public static final Animation MODERN_TELEPORT_ANIMATION = new Animation(714, 0);
public static final Graphic MODERN_TELEPORT_GRAPHIC = Graphic.lowGraphic(308, 0);
change those IDs to whatever you want. ez