but I need to intercept the calls to my method before they happen. By analyzing your source code, I've found that
every server side method is callled by the code on the line 144 of DispatcherBase class
I just forgot to tell you that the portable way to intercept a method call is to create your own Dispatcher that extends SsmDispatcher: you can get what you want that way, without having to hack DJN code base.

Check how SsmDispatcher is used and registered for details.