Sorry for not having been very clear it was a little bit blurry for myself :p
So in fact I ve solved my "problem" by creating another project "MyAppliAPI" where I set the EventDispatcher to communicate with the MyAppli.
And on the subbaplication and module side :
this.myAppliApi = new MyAppliAPI(this.systemManager.loaderInfo.sharedEvents)
On the "MyAppli" side (where I load the subapplication) I created a new Class "MyAppliAPIBridge" where I set the EventDispatcher to communicate with the subapplications. This has to be the same as the one set in "MyAPI".
For subapplications (Application) it is :
this.myAppliAPIBridge = new MyAppliAPIBridge( swfLoader.content.loaderInfo.sharedEvents);
After that the subapp had been loaded. (code in the MyAppli)
For Modules :
this.myAppliAPIBridge = new MyAppliAPIBridge( this.systemManager.loaderInfo.sharedEvents)