Not a tutorial, just a video showing it. I'm to lazy to edit out all the failed attempts, so just skip to 9:14 for when I finally get it.
Recorded using NTR CFW on FW v11.0. My settings are: quality = 70, qosValue = 101.

How to do it:
1. Move the enemy in front of the portal using the hookshot (make sure he's facing down).
2. Damage yourself, then hit the enemy with the hookshot and walk into him, then use the tornado rod while your I-frames are still active.
3. Use bombs to get far enough into the wall.
4. Push Down+Left and then use the tornado rod one frame later. This is the hardest part of the trick.
5. Navigate around the wall and jump down to the OOB pillar.
6. Position Link so his shadow is in the middle of the fourth square to the left.
...
https://www.youtube.com/watch?v=5hcBwW32YPI