you guys have to add each other first. Then both of you connect to Mognet, and it doesn't have to be at the same time (this updates the Nintendo Wifi and makes it so the
FC are not grayed out). Now you guys can send each ther messages. After you recieve the first message from that person his
FC will change into his name (000000000000 --> John). Also the HUB does nothing, its not connected to your games/wifi in anyway - it's only purpose is to allow poeple to communicate in real time whcih makes setting up games easier. Incase you don't know you only have to send 7 messages total to unlock the side quests (they can be to one or more persons)
Example to illustrate:
-2 people want to trade
FC's, lets call them Joe and Mac
-Joe and Mac add each others
FC (they are still gray atm)
-Joe gets on Mognet to update his Wifi status (both
fc are still gray)
-Mac gets on Mognet (Now Mac can send Joe letters but Joe still cannot)
-Joe gets on Mognet *again* (Now Joe can send letters to Mac and vice versa)
-Upon recieving each others letters the
FC change into each others names