Oh my god, I understand this now.

I downloaded a 30-day-trial while at university, since I didn't have my original at hand, tried the damn testcode again and it worked.
Super happy, saving the files, going home aaaand... it doesn't work.

Looking at the website:
Isometric view needs Pro-Edition and I only have Extra.
I cannot use this feature

I was a step away from explaining how to manage tiles with a shader. What a pity!