An add-in can add one or more menu points to the "Utilities" menu of EPLAN. There fore the class Eplan.EplApi.Gui.Menu provides a function addMenuItem which has to be called in the OnInitGui() function of the add-in module class:
The function AddMenuItem() adds a menu point with the text "CSharpAction" and assigns the action "CSharpAction" to this menu point.
Menu points always have to be assigned to an action. this means you need to implement a new action in your add-in or you could assign the new menu point to an already existing action.