Lua menu items questions

I see in the testmodule demo how to create menu items for teamspeak and how to add an Icon for it.

My question is, Is it possible to update these menu items after they have been created.

Specifically I'd like to set an Icon for On, and an Icon for Off, and when I select the menu item it will toggle to the alternate image.

Along the same lines can I update the text on the menu items also after it has been created.

One last thing, is there a way to create submenus for my plugin ? So when I create a menu for my plugin it would have a submenu titled with my plugin name and the menu entries underneath the submenu.

Thanks
Bob

Lua menu items questions