I have somehow screwed this quest up. Long story short, I need the Elder Scroll, not the one I get from the Soul Cairn, but the other one.

How do add that to my inventory? I use the command line:

player.additem 0002d513

Just like that, but nothing happens, am I typing it wrong or what is up?

Do you mean the dragon scroll? If so, where did it go? Did you sell it to Urag? If so, you can just buy it back from him for 2,000 septims.

Nevermind ;0)

I didn't take the scroll the first time I had the chance, didn't know it was inside the machine at Blackreach. Did lots of quests afterwards and the quest kinda got blocked. And when I got back to Blackreach to pick up the scroll, it wouldn't update my quest or add the scroll to my inventory.
It was all a mess.

But now I've got it all working again.