The Wowza Pro server does not support ActionScript on the server side (main.asc). So yes, you would need to recode this functionality in Java using the Wowza Pro server side API. The API is documented (document
Server Side API Guide and
FMS to Wowza Pro API Mapping) and the
Creating a Custom Module chapter in the
User's Guide walks through the process of creating a Java project in Eclipse. I suggest you walk through this example and give it a go. Just ask lots of questions on the forums and we will jump in and help.