Very nice, thank you!
Still work in progress though, I'm afraid.
In CKEditor I now get the dropdown-list with all the OneForAll items, so that is great.
In the source code, I can see how the item is 'called', for instance:
<a href="[wblink23?addon=oneforall&item=27]">OFA item</a>
However, when it's saved, and I check the live page (frontend) and the link is turned into
<a href="#">OFA item</a>
I must add: I use ShortURL. Maybe that's causing problems?