First of all, "ik mag er zijn" literally: "I may be there / here" but what is meant in this case is something like "I am worth existing; I am valuable". A form of expressing someone is confident or proud of himself, in a positive way. Let me know if that is not clear, it is a bit difficult to explain but I'll be happy to try again
As for this request, the meaning is pretty accurate. I would say 'notify' instead of 'announce'. Also, is Charalampos a Greek name? In Dutch it says charalabos.