Well, now we should create a submenu item renderer Movie Clip in the website.fla. We can just duplicate the MainMenuItemRenderer MovieClip. So, let's find it in the library in Modules - MainMenu Assets, right-click on it, and choose Duplicate in a context menu.
We name it MainSubMenuItemRenderer.
The duplicate was created in the MainMenu Assets folder, where the MainMenuItemRenderer is located. Let's move MainSubMenuItemRenderer to the MainSubMenu Assets folder.
Then we right-click on it again and select Linkage Properties in a context menu.
We check Export for ActionScript box. Class: MainSubMenuItemRenderer, as we have specified in the structure.xml. Base class: modules.MainSubMenuItemRenderer.
Now let's open this Movie Clip and make a duplicate of Movie Clip which contains the background shape.
Then we go to the second keyframe and swap the symbol.
Important: Swap it in every keyframe on its layer.
Then we open the copied Movie Clip and change the shape's color to blue to make a visible difference between MainMenuItemRenderer and MainSubMenuItemRenderer.
And, finally, let's move the duplicated Movie Clip to the MainSubMenu Assets folder.