This bug was originally reported at http://bugs.mandrakelinux.com/query.php?bug=1158. The maintainer thinks this is an upstream bug; thus, I'm reposting it here and hope that a proper fix is in place.
I've upgraded to 3.0.8, and changed security = ADS in smb.conf. Now Samba creates lowercase computer_name folders in homedir instead of uppercase user_name folders. Please see http://bugs.mandrakelinux.com/query.php?bug=1158 for more information. I think this is a serious bug. Many users on samba-users list also saw the same thing, but couldn't find a solution to it. My report on samba-users could be find here, http://marc.theaimsgroup.com/?l=samba&m=110256134212709&w=2. Folder names were still in uppercase because I was using 3.0.6, but everything else are same. So I didn't bother with a capture for 3.0.8.
This is intended behavior See BUG 722.