has most of what you are looking for. Usually for iPlanet, the following is the process
Plugin for NES/IPlanet is provided as .so file.
Copy it to the iPlanet's server /bin directory.
Edit obj.conf to forward certain requests.
Hope this helps.
You may want to seperate the web layer(iPlanet) and the app server (WLS) physically (different) boxes for security reasons. I am not sure if the plugin would work better if WLS and iPlanet were co-located on the same box. They would probably use local IPC instead of sockets, but I am not too sure. But the rule of the thumb is seperate the web and app layers and have images and static content hosted on iPlanet.