Dear Andrea Moldoveanu,
Please following the steps:
1. you need create menu item pointer to k2 category
- go to administrator -> menus -> menu manager -> create menu -> hidden menu
- go to administrator -> menus -> hidden menu -> add new menu item:
+ Menu Title *: your_menu
+ Menu Item Type *: chose k2 -> k2 categories
+ Select one or more categories: chose your category (is category chosen in SJ K2 Accordion module)
2. set up others modules display on menu item above (your_menu).
- go to administrator -> module manager -> edit module -> Menu Selection: chose your_menu
Thanks!