[Samba] File permission problems after update from Samba 4 alpha 17 to Samba 4.0.5

[X-Dimension]

We had used Samba alpha 17 (included in Resara Server 1.2) for a long 
time and
has now migrate it to Samba 4.0.5 (Ubuntu + Zentyal 3.0 PPA) with NTVFS 
enabled .

Most things seems to work: DNS with Bind9_DLZ, domain join, user login 
and also GPO are still working fine :)
But we have trouble with file permissions now!
All domain users can't rename or delete their own files which they had 
created with Samba 4 alpha 17 before.
It looks like they only had 'read only' access to their files.
For example when the user peter at mydomain wants to rename/delete a file 
he had created before, then he
gets an error message like "only peter at mydomain can rename this file" or 
"file is locked by peter at mydomain".

Our global section of /etc/samba/smb.conf looks like this:
--
[global]
     interfaces = eth0
     workgroup = MYDOMAIN
     realm = mydomain.lan
     netbios name = PDC
     server string = PDC
     server role = active directory domain controller
     passdb backend = samba4
     server services = rpc, nbt, wrepl, ldap, cldap, kdc, drepl, 
winbind, ntp_signd, kcc, dnsupdate, smb
     dcerpc endpoint servers = epmapper, wkssvc, rpcecho, samr, 
netlogon, lsarpc, spoolss, drsuapi, dssetup, unixinfo, browser, 
eventlog6, backupkey, dnsserver, winreg, srvsvc
--
Because Samba 4 alpha 17 was using NTVFS, i thought it is the best idea 
to stay on NTVFS even on Samba 4.0.5.
But it looks, like i was wrong.

Thanks for any ideas that helps us to fix our permission problem.