You are going back a ways with version 7, but the basic setup hasn't changed a huge amount if I recall correctly.
I'm not sure what you are trying to do, though. Do you just want to set up two teams of all star players to play against each other? Are you trying to make a league only of all star players to play against each other?
I should also ask if you have played the computer version at all. Do you know how to set up leagues and teams?
To play games you need to have defined a league. That league can be the same teams and player rosters exactly as they come on the disks, or you can make up completely different leagues with different teams and player rosters.
If all you want to do is play one game between two teams, you still have to create the teams with the players you want on them in order to have the two teams play against each other.
For example, if you are playing a strat computer league and want to hold an all star game at the break, you would make up a seperate league with two teams, copy the all star players you want to use from the current league team to the new teams, set them up as you would any team, and then you can play one game or ten or however many you wanted.