Custom WSS Configuration via Plugin

I am attempting to figure out a way to override the basic Outgoing WSS configurations to add additional WssEntry types. I originally modified the open source code to achieve the effect I was going for, but I want to accomplish this as a plugin (if possible) so that it can be distributed to other teams.

I can't seem to find a way to override the interface for the WSS configuration (WSSTabPanel), which may be a limitation of the plugin system. There may be other ways I can accomplish the same goal, but I was hoping for some guidance on how I might add my own WSSEntry that calls my own custom SAML callback classes. If this is not possible, that information would be helpful too.