Illustrator SDK :: How To Create Extension (flex - Extension Builder)

I'm learning how to create extension (flex - extension builder) for Illustrator and how to make it communicate with a plugin.

The samples provided in the SDK detailed how to load /unload extension from a menu item from Illustrator, and how to add / remove EventListeners to make the magic happen.
 
to sum up, this is something like that:
1- click on the menu item
2- load extension
3- add listeners
4- do your stuff......
5- remove listeners
6- unload extension
 
Basically my plugin is a module/service which is in charge of dealing with / modifying artwork tree. It has no User Interface.

My extension will have a user of this service.  
 
What I would like to do is to load my extension as soon as my plugin is loaded, and unload the extension when the plugin will be unloaded.

Or notify when extension is loaded or unloaded.

Is that possible and hw could I achieve that?