Help with accessory belt install?

[VW-Fritzi]

I’m trying to install a new A/C accessory belt on an E70 N62tu. The tensioner is this model with a slotted bolt and a second fixed bolt.



I can reach the slotted bolt to loosen or remove it, but I can figure out how to reach the fixed bolt, which I’m guessing needs to be removed so the tensioner can slide down and allow the belt to be positioned.

The fixed bolt is facing straight down. There is so much other stuff in the way though, so I can’t reach it even with a very long extension and a universal joint. Even if I could, I’d never be able to get my hand in there to get the bolt back in place when I was done.

Is there some other way to get the belt on without removing or shifting the tensioner? Or am I missing some way to get access to the second bolt?