May I ask what´s the difference between your portal and the other ones? Kihakus portal does exactly the same as yours...
As for the hl portals: That´s a stunning effect. Basically you´ll have to determine the directions of the portals. Then apply the right forces to the touching objects. After disapearing in the wall you have to "teleport" them between the first and the second portal. After that, use the direction to apply some new forces. That _could_ work.
