[Samba] File Permision Setup for Security

[Jerrynikki]

Hai all,

how i can avoid other users editing and deleting my files thats in samba share...
there is more than 1000 users in my network
all users are authenticating to Windows2003 ADS,

they cant  delete others users files.. thats in samba but they can edit it..spoil it
how i can avoid it... 

here is my corrent samba configuration

[global]
   workgroup = MYDOMAIN
   server string = Samba Server
   log file = /var/log/samba/%m.log
   max log size = 50
   security = ads
   encrypt passwords = yes
   socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192 
   dns proxy = no

#== Share Definitions ==#
   #ldap idmap suffix = ou=emplist,dc=dqe,dc=com
   password server = 172.16.20.200
   realm = MYDOMAIN.COM
   idmap uid = 16777216-33554431
   idmap gid = 16777216-33554431
   template shell = /bin/bash
   template homedir = /home/%D/%U
   allow trusted domains = no 
   idmap backend = idmap_rid:DQE=16777216-33554431
   winbind use default domain = yes

[vol08]
   path = /vol08_700
   writable = yes
   public = yes
   nt acl support = yes
   create mask = 0755
   security mask = 0755
   inherit permissions = yes
   inherit acls = yes
   force security mode = 0
   directory security mask = 0777
   force directory security mode = 0

hope some one can help me.....
Thank You in Advance,
Jerrynikki.