Could I get some help with getting MessageHandler for a WiiInputInterface?

InputInterface classes (I.E. XInputInterface) provide access to controllers (i.e. 360 controller for windows, or a keyboard or mouse)

They send messages when buttons are pressed or sticks are moved via a MessageHandler

The MessageHandler is provided by *Application (WindowsApplication, LinuxApplication, e.t.c. when the application initialises the *InputInterface, and if GenericApplication->SetMessageHandler is called on an *Application it updates its *InputInterfaces MessageHandler refrences…

I am making a plugin for using Wii Inputs, and rather than using an actor, I was wanting to make a WiiInputInterface, however I’m not sure how to get a reference to the *Application’s message handler without breaking the cardinal rule of plugins (that they are self contained, and therefore shouldn’t need custom code in the *Application.cpp

Anyone know how I can lookup the *Application MessageHandler properly??