That is how it's supposed to work.
The sorting topic is added to him by default, as part of his initial greeting, as I recall.
To actually sort books you just ask him about "organize books" while you have some books in your inventory.
Last time I tried it, it worked perfectly for me.
Have you tried redownloading and reinstalling a fresh copy of the plugin?
I'm not sure what else could be causing it.
From what you said, there really shouldn't be any problems at all, and I've never heard anything about Julan being incompatible with UL.
Hmm... I keep hearing about UL having so many issues recently.
Maybe I should do something about it myself.
For example, Stuporstar made UL compatible with my Bathing Mod, but when I last tried using UL, it didn't work.
I tested it, and somehow UL causes the whole Bathing Mod to stop working. (You couldn't actually take baths...
anywhere.)
When I just removed UL, my Bathing Mod began working properly again.
I was planning to make a small addon for UL, to give Tel Uvirith some Better Bodies mannequins, and some extra storage.
If I bothered to do that, I could just as well try to make it into a bugfix patch, as well.
I can't promise that I could fix
everything, but it could be worth a look, at least.
Regardless, I can't do it right now, as I'm still tied down with my current project.
As soon as I'm done though, I'd be quite happy to look into this, if anyone is still interested.