Registered as a .net passport? Ok try signing onto msn with your gmail address. If it is registered you are fine to use that email. If it is not registered you will not be able to change your name to anything but your email. So when other people see you on their list it will just say
[email protected]. To fix this, msn should be giving you an option to register your gmail address as a .net passport.
Here you go. Nice an simple.