I've received the PDF for creating your own plugin. What this document is missing, however, is any required Class name for the interface implementation. I've created my DLL via C# and called it from my own C# project. The interface implementation works. I am able to call GetFriendlyName() through the interface and get back my string. When I place the DLL in the correct folder for OnTime and load the SCMSettings table, I still cannot get the plugin to appear in the SCM drop down.
I believe this is because OnTime doesn't know the name of my implementation class.