Yep, according to the FAQ, installing 10 additional per-user CALs on the SBS server will cover you, as long as you've also got adequate Terminal Server CALs for Server2. (Since you didn't mention TS CALs, I'll assume you're covered there.) Unfortunately, I'd say that the 10 per-server CALs on the 2003 Std server were not necessary. Was that server being used before SBS was installed, by any chance?