iCloud on my iPad 2 defaults to incorrect email address

I'm still having issues with iCloud on my iPad 2.

My inactive MobileMe account was moved to iCloud with no problems when I went to iCloud, but for some reason my iPad 2 defaults my mail address to <name>@mac.com rather than the one that works - <name>@me.com. There does not appear to be any way to change this as the email address is greyed out in the Settings/iCloud/Account/Mail section. In my Apple Id I have listed the <name>@me.com address as being the default mail address, but for some reason iCloud is ignoring the default.

I have tested both mail addresses postng to iCloud - when posting to <name>@me.com the mail comes through fine. When posting to <name>@mac.com the server returns a transmission error: "Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 5.1.1 unknown or illegal alias: <name>@mac.com (state 14)."

The consequence of all this is, of course, that I cannot get mail from my iCloud account on my iPad. This is not a good thing.

Any thoughts please anyone?

PS: Obviously the "<name>" above is a placeholder for my real name... 😝