Real Video 8 is available from the Real Media 9 plug-in:
1. In the Render As dialog, select the Default Template and click Custom.
2. Go to the Audiences page, click the Edit button.
3. Change the Encoding Type dropdown to Constant bitrate
4. Now look in the video codec dropdown, and you'll see you also have Real Video 8 as an option.
5. After you set everything as you want, type in a new name for the template, update the description and click the Save button (icon looks like a floppy disk). You'll be able to use this template for your renders.