This is currently not possible as the same template is used that's shipped.
Please note that this is done on purpose because with each new version of WebIQ we can modify the corresponding JavaScript templates because of changes or new features which guarantee that it'll work.
This feature would actually infer using a different template which would mean that there would have to be some kind of JavaScript template management included in WebIQ Designer for you to pick the template which would definitely be a larger feature.
However, you could of course have your template locally and simply copy, paste & modify your template. Usually our HMI users don't have a lot of scripts in their HMIs so I don't think this would be a feature many customers would require and there may be areas in WebIQ Designer where improvements would infer more benefits for all users.
