Only the CALs are trial. AFAIK this is the only thing you have to add for a reals BES10
I use the same service account for BES5 and BDS. Actually, the permissions for the BDS service account are less then for the BES5 service.
regarding the CALs:
They will work on both servers until the end of the trade up period.
http://www.blackberryforums.com/bes-...ml#post1800275