Change iCal events to Floating time zone?

I have a lot of events in Mountain Lion’s calendar, and I’d like to switch all of them to Floating time zone. Is there a script that can do this in bulk, or do I have to go in and manually change each one?

Also, there doesn’t seem to be a way to create a new event with Floating time zone as the default choice. Is there a script that can do that?

Thanks in advance …