Technically, you should be able to get to it using the .lookup("scrollbar")
method after the skin is initialized (if the scrollbar is visible). I don't like that answer though.
I don't think you're missing anything according to this bug ticket:
- How to access to ScrollBar component in ScrollPane control ?
https://bugs.openjdk.java.net/browse/JDK-8091864
I'd encourage you to jump on that, present your use case, vote, and see if you can get some sort of response in the future.