first go to the super class of your view implementation class change into edit mode and then go the methods tab and change the visibility to public of that outbound plug. activate the super class. thenc ome the normal view class. if you do syntax check, then it will show one error like you can not change the visibility of inherited methods. becuase we have changed its visibility in the super class and we need to do the same in the child class.
go to the source code based view and move the redefintion of outbound plug from proctected section to the public section and activate the child class also. when activatng choose all entries in the list.
you can find detailed information in the blog i mentioned.