The plugin is working almost as it should...or it probably is but something wrong with my conf. I'm using callback function which is pretty much the same as the example in the twentyten theme functions.php.
But for some reason when replying to a comment the reply doesn't get the proper classes (depth-2 etc.) and therefore renders as it was the depth-1 comment (gets those classes). After page refresh it does render correctly as depth-2.
If I disable the callback, then the class is set properly so my guess is that this has something to do with the callback function and how it's set up but I can't figure it out... Or could it be something else?