You really don't, and I checked to be 100% sure that nothing has changed in Wowza Engine. You can create an empty folder named "testvod" to the [install-dir]/applications and use testvod immediately for simple video on demand streaming.
However, the Manager will not list this application on the Application page, so you can't modify it through the manager. At least at present, you have to create applications with the Manager to be able to modify them in the Manager.. Actually you just have to restart Wowza Engine and Manager.
If, perhaps, you are using .stream files, and adding them to StartUpStreams as part of your work-flow, you would then have to re-start Wowza, because StartUpStreams starts these streams when Wowza starts. You can start a single stream without adding to StartUpStreams and re-starting. If the live source is an RTMP live encoder (like Wirecast or a Flash app used as encoder) then you don't have to re-start Wowza to start streaming with a newly created application.
The current scheduler supports one scheduler per application, but it can have many streams defined in that schedule. It is Wowza that reads the smil file, creating server-side streams. The source of these server-side (Stream class) streams can be a file, or another live stream.