Actually you can build them up with either the TE or OE but I don't have time right now to detail how to build them in the OE.
Diablomax if you look closely at your OE built fleet, the gun batteries on your ships are missing or look funny, it's cause by a subtle error on your part. As NHawk suggests, use the TE to build your custom fleets because it's more straight forward and quicker to modify if you change your mind.
Set the standard cvtg group object then delete, add or move the ships as you want. Don't mess with the CV if you want to man the gun positions, it's the group master and the hanger/gun position are hard coded.
Oh, and move your ships, save, exit and reload.