UCS joining a MS AD 2003 - not all users ported. Are there solutions?

After joining UCS to MS AD SBS2003 I have some users ported to the UCS, but not all! Some of ported users are disabled long-time ago. Also, there are special accounts like Guest, Internet Guest Account, SUPPORT_388945a0. On the other hand a couple of active users are not accessible, they are missed. Thus making UCS useless at all.
Does anybody know how to check AD synchronizing logs? Where shall I look for them? What shall I check to assure I didn’t miss something?