Importing a Custom Component in to Scene builder

Question

There are many similar questions but i am not sure what i am doing wrong,

below are my two classes,

class 1:

public class CustomTreeTableViewColumn extends JFXTreeTableColumn {

    public CustomTreeTableViewColumn() {
        super();
    }

    public CustomTreeTableViewColumn(String text) {
        super(text);
    }
}

class 2:

public class CustomTreeTableView extends JFXTreeTableView {

    public CustomTreeTableView() {
        super();
    }
}

JFoenix version : 9.0.8 JDK Version : 11 Scene Builder : Gluon 10.0.0

When i try to import above classes as jar in scene builder i see no UI components.

So i tried this following example,

SceneBuilder - Add custom component which relies on third party components

Custom FXML component (w/ controller) doesn't appear in SceneBuilder's "Import jar" dialog

but nothing seems to work.

How can i import these custom components in Scene builder?