I'm having some problems with the accepting of calendar invitation.

All our user have a shorthand user name like chrisgu@domain.com and have an alias of chris.guthrie@domain.com which is there full name. (all account come from AD so can't be changed)

We want all communication to go via the FirstName.LastName alias but this doesn't seem to work for calendar entry. If I add an invitation to someone and they accept it via the webclient the response alway comes from their username@domain.com instead of the canonical FullName.Lastname address.

Is there a way to force the calendar system to use the canonical address like it does for normal email.