If you are using the Wowza Transcoder, and your clients are connecting to the Wowza server that transcoding, using StreamNameGroups, as described in the Transcoder guide. You do not have to create a smil file in this case, what the player gets from Wowza is the same thing, generically called a MediaList.
If you are using Live stream repeater where your playback clients are streaming from edge servers, then you must put a smil file on each edge, and Wowza does provide a way to automate the creation of this smil file, following this guide
You may need to modify the created smil for the .stream names you are using on the edge, but the codec and bitrate info will be populated for you.
Richard