Set window icons for Alerts

[Hely0n]

Setting icons in the JavaFX way, they won't be set. So the following expression isn't effective when using TornadoFX:
(alert.dialogPane.scene.window as Stage).icons += (Image(getResStream("/desktop/images/dialog-warning.png")))

Is there another way to achieve this?
The "alert()" builder from TornadoFX seems to create the same Alert object as the Alert() constructor, so there are no functions like openModal() available, which would return a Stage in which icons could be added.