Extend notification item - workmanager

Hey all,

i am trying to extend the notification item in workmanager.

to do that i tried override setItemParameters by extending NotificationPostBAPI  as you see below,

As you know that one notification can have more that one item and NotificationPostBAPI   post those into IT_NOTIF_ITEM.

is it possible to extend this bapi as you see below or do i have to extend notification, notifitem also.

I thought that to be able get the "i"  in the setitemparameter method woud be enough but how can i get that ?

Anyone has experience with extending the items of notification can help me?

Thanks..