I have a N9 (PR1.1 20.2011.40-4.480.2_PR_480). I have added an MfE account which works without any problem (but one). The problem I have is, that to every email I send out a "@localhost" CC is added. The other clients of my Debian MTA have no problem whatsoever. The log file of the MTA indicates that it already recieves the localhost CC. Therefore I believe it is a N9 problem.