Roger,
Yes, use MediaCache, and it is built-in to those pre-built AMIs. You will configure MediaCache in that application, except that you will leave the Application.xml /StreamType “live”, instead of “default” which is typical with MediaCache, but it will work with scheduler app so the file assets and .smil files can be stored on S3.
Highly recommend upgarding to Wowza 4.04 with AWS Marketplace AMIs, which are EBS backed volumes which can be stopped and started.
Richard