Take a look at these 2 events. If you use 2 paddles exactly 1 WindowWidth apart and both with all the same behaviors (remove the wrap behavior), this will give you exactly what you want.
The reason the example you found doesn't work is, it just moves the paddle to the other side of the screen. You can't split the paddle into two pieces to show on either side. My version fakes splitting the paddle by using 2 paddles. As 1 leaves the screen, the other enters the screen. When the paddle off screen gets too far to the left or right, it jumps to the opposite extreme. Since it's off screen when it jumps, the player never sees it and it just looks like the paddle is wrapping around.
The attached capx shows how my method works.
[Edit] modified the attachments to fix a bug