Eclipse/Java9: how to access internal javafx packages?

My context:

• Eclipse IDE for Java Developers, Version: Oxygen.1a Release (4.7.1a), Build id: 20171005-1200oxygen
• jdk9.0.1
• win10

Something simple like:

import com.sun.javafx.scene.control.LambdaMultiplePropertyChangeListenerHandler;

import javafx.application.Application;
import javafx.stage.Stage;

public class ImportCom extends Application {

    @Override
    public void start(Stage arg0) throws Exception {
        new LambdaMultiplePropertyChangeListenerHandler();

    }

}

won't compile due to

The type com.sun.javafx.scene.control.LambdaMultiplePropertyChangeListenerHandler is not accessible

What to do?

looks similar but now for internal classes ;) Had been compiling until patch 530 of the beta9 support but not after - so keeping that oldish oxygen as a gold treasure ...

Note: cross-posted to eclipse forum

Edit:

Just checked that the behavior of javac on the commandline:

C:\Users\kleopatra\ox-1a-64\dummy\src>\java\jdk\190-64\bin\javac first\ImportCom.java
first\ImportCom.java:3: error: package com.sun.javafx.scene.control is not visible
import com.sun.javafx.scene.control.LambdaMultiplePropertyChangeListenerHandler;
                           ^
  (package com.sun.javafx.scene.control is declared in module javafx.controls, which does not export it to the unnamed module)
1 error

The error is similar to the one in Eclipse. Works fine with --add-exports:

C:\Users\kleopatra\ox-1a-64\dummy\src>\java\jdk\190-64\bin\javac --add-exports=javafx.controls/com.sun.javafx.scene.control=ALL-UNNAMED first\ImportCom.java

So the question boils down to: where/how to configure Eclipse such that it compiles access to internal classes just the same way as javac?