Assasins creed 2 help plz

hi
First mission after ezio talks to his father and then his father asks him to deliver documents to somone.....after the conversation ends and i accept the mission when i go out there is no any marker on the map shows where i have to go..i viwed every tower or whatever its called.......after the eagle vision it says MAP UPDATED.....but i seee nottttttttttttttthing on map??? help plz