Flexiaccess: Menus missing in "Frontend & Content"

I'm trying to set up access permissions for some menu items via Flexiaccess. Having issues with the "special" user group and error 403 I came across the following article: www.flexicontent.org/documentati ... items.html
I have about 10 different menus on my site but Flexiaccess shows only three of them and the menu I need to set up is not among them. Shouldn't Flexiaccess list all menus on "Frontend & Content"?

I am not sure about this, maybe try to set your menu item acess to "Special" (and every time you edit the menu item do not alter the access), then visit FLEXIaccess backend to check if they appeared

The strange thing is, that the complete menu is missing:
E.g. my main menu. All items of this menu are public but this menu doesn't show up in Flexiaccess. In fact the only menus that show up in there are the usermenu and two small login menus. These menus have in common that they contain mainly user related items.

If i remember correctly , the menu will not show unless you create a menu module that uses it

I don't think that this is the reason since both, my main menu and my top menu are displayed in menu modules sitewide