Add property/function on existing type in TypeScript typings.d.ts Leaflet (JS to TS)

I'm trying to implement the typings (typings.d.ts) on a Leaflet Plugin. The aim is to make the plugin available on my Angular TypeScript project. I understand the logic of typings but I don't succeed to implement it, my TSLinter continue to generate errors.
The plugin is working properly but the TS Errors as annoying.

• Property 'movingMarker' does not exist on type 'typeof Marker'.
• Property 'addStation' does not exist on type 'Marker'.

https://github.com/ewoken/Leaflet.MovingMarker

My code block that is using the library :

import 'src/assets/js/leaflet-movingMarker';

...

this.messageIcon = create_icon('message', 40, '#f5af19', 'This is a message');
this.messageMarker = L.Marker.movingMarker([ // << error : Property 'movingMarker' does not exist on type 'typeof Marker'.
   L.latLng([this.a.Lat, this.a.Lng]),
   L.latLng([this.b.Lat, this.b.Lng])
    1000 * 2,
);
this.messageMarker.addStation(1, 1000); // << error : Property 'addStation' does not exist on type 'Marker<any>'.
this.messageMarker.addStation(2, 1000); // error
this.messageMarker.start(); // error
this.messageMarker.options.icon = this.messageIcon;

My typings.d.ts file :

import * as L from 'leaflet';

declare module 'leaflet' {
    interface MarkerOptions {
        autostart?: boolean;
        loop?: boolean;
    }

    interface Marker {
        movingMarker(latlngs: L.LatLng[], durations: Number[], options?: Object): Marker;
        addStation(pointIndex: number, duration: number): this;
        start(): this;
        isRunning(): this;
        isEnded(): this;
        isStarted(): this;
        isPaused(): this;
        resume(): this;
    }
}

I think, it is this plugin's part which is the most problematic :

L.Marker.movingMarker = function (latlngs, duration, options) {
    return new L.Marker.MovingMarker(latlngs, duration, options);
};