To test RT-3099, I installed a fresh install of Vista on my Mac-based VirtualBox. Once Vista was installed, I backed up the virtual disk file so I could easily return to a fresh install state. Running a JavaFX app via Firefox 3.0.5 brought up the expected "Java needed. Click for details." message. Clicked message, got "Install java?" Dialog, clicked OK. Was taken to the Java install page, but install did not start automatically. Manually clicked button to install, and once complete, had to exit Firefox and manually reload the page in order to run the applet.

So, workaround for the issue is to install Java manually, and then restart Firefox and reload the page.

After this, I uninstalled the JRE via the Control Panel. I then started Firefox and loaded the JavaFX page. Again, got the "Java needed" message, clicked, got the "Install java?" dialog, and click OK. Java installed automatically and page reloaded.