I just set up vansihnopacket and i need to know how do i notify my staff automatically when they join?

There is a permission vanish.statusupdates to notify permission players.

You can also write a Bukkit plugin with this code:

@EventHandler
public void onVanishStatusChange(VanishStatusChangeEvent e) {
    for (Player player : Bukkit.getOnlinePlayers()) {
        if (player.isOp) { // you can also check permission
            player.sendMessage(e.getName() + "'s vanish is " + e.isVanishing());
        }
    }
}

I'd probably vote for the permission node vanish.statusupdates over writing an entire plugin just to replicate that functionality :P

Due to #608 I will restate:

Grant the node vanish.statusupdates

For other permissions, see http://dev.bukkit.org/bukkit-plugins/vanish/pages/permissions/