samba - May 2002 - Problem with locking files in MS Mail Server

Hello Everybody.

I have problem with samba (debian potato 2.2.17 with samba 2.2.2), when
I'am using samba to share "normal" files - everything was ok. But
I must
still use Microsoft Mail (messaging system) to deliver local messages in
my network. Last time, I move this server to samba (before was on NT
3.51 :-)), and I have problem:

When some part of my clients open MS Outlook with client MS Mail files
after operations (send, receive) on samba server files with mailboxes
still are locked. This message server is organized like a set of
folders, were messages are stored. The biggest problem is locking files
with status of specific mailboxes. 

What can I do?

This is my smb.conf

[global]
   invalid users = root
   
   security = user
   
   map to guest = Bad User
   
   workgroup = workgroup
   server string = IntraNet Serwer
   netbios aliases = NHSERWER
   netbios name = KOGA
   
   syslog only = no
   syslog = 2;
   socket options = IPTOS_LOWDELAY TCP_NODELAY SO_SNDBUF=4096
SO_RCVBUF=4096
   
   character set = ISO8859-2    
   client code page = 852       
   wins support = no
   
   os level = 20
   domain master = no
   local master = yes
   preferred master = yes

   name resolve order =  host lmhosts bcast wins 
   dns proxy = no
   preserve case = yes
   short preserve case = yes

   encrypt passwords = yes       
   unix password sync = true
   passwd program = /usr/bin/passwd %u
   passwd chat = *Enter\snew\sUNIX\spassword:* %n\n
*Retype\snew\sUNIX\spassword:* %n\n .
   max log size = 2000
   log file = /var/log/samba/log.%U

   veto files = /*.eml/*.nws/riched20.dll/
   deadtime = 5
      
[msmail]
   path = /home/samba/msmail
   guest ok = yes
   guest account = msmail
   writeable = yes
   force create mode = 0777
   force directory mode = 0777
   veto files = /*.bat/*.rar/*.scr/
   locking = no