What I have found out in other forums of the individual carriers (esp AC's) is that one problem is that the Star Alliance carriers ticketing agents can not issue a ticket for another Star Alliance carrier (unless a RTW ticket involving at least the host carrier, or a ticket involving at least 2 airlines, including the host carrier), or seat selection/changes on another carrier (even if the ticket is in the form a of code-share by the host airline on the other carrier).