Look into these links:
1 - GitHub - empirephoenix/JME3-JFX: JFX Gui bridge for JME with usefull utilities for common usecases
2 - JME3-JFX/TestTextureContainer.java at master · empirephoenix/JME3-JFX · GitHub
3 - Virtual interactive Computer Desktops
The only “bad” thing is that it needs Java 8 installed during development and is not really well integrated with jME SDK (at least jME SDK 3.0 is a bad partner for JME-JFX).
@Empire_Phoenix seems to be the person to who you could send a PM. I think he’s German (if you’re not that good in English).
EDIT: posted the same link twice - sorry for that ^^