A few possibilities. Firstly you want to make your VOD assets compatible with Wowza. This means encoding or transcoding your MPEG2 files to H.264. You can do this on the fly using the transcoding capabilities of various players such as VLC or ffmpeg. This can then be published into a Live Wowza application.
Another option is to permanently encode your MPEG2 files to H.264. This can be as simple as running something like the following (if you have ffmpeg command line tools installed):
This way you can then play these files within a Wowza VOD application which gives you more control over scheduling of content etc.
ffmpeg -i source.ts -vcodec h264 destination.mp4