Samba: force directory mode is ignored

Setting up a new samba-fs I got following problem:
the parameter force directory mode = 0775 is totaly ignored, even when setting unix extensions = no.
If I create a new dir from am Win7 or XP client I'm getting the permissions drwxrwxr-x. Copying a directory gives drwxr-xr-x.
Doing the same with a file I'm getting permissions set according to what I've defined with "create mode" or "force create mode".
Using a smb.conf from a slightly older system (11.4) wich is perfectly working didn't help.

output of testparm -v :

        lm interval = 60
        preferred master = No
        local master = Yes
        domain master = Auto
        browse list = Yes
        enhanced browsing = Yes
        dns proxy = No
        wins proxy = No
        wins server =
        wins support = No
        wins hook =
        kernel oplocks = Yes
        lock spin time = 200
        oplock break wait time = 0
        ldap admin dn =
        ldap delete dn = No
        ldap group suffix =
        ldap idmap suffix =
        ldap machine suffix =
        ldap passwd sync = no
        ldap replication sleep = 1000
        ldap suffix =
        ldap ssl = start tls
        ldap ssl ads = No
        ldap deref = auto
        ldap follow referral = Auto
        ldap timeout = 15
        ldap connection timeout = 2
        ldap page size = 1024
        ldap user suffix =
        ldap debug level = 0
        ldap debug threshold = 10
        eventlog list =
        add share command =
        change share command =
        delete share command =
        preload =
        lock directory = /var/run/samba
        state directory = /var/lib/samba
        cache directory = /var/cache/samba
        pid directory = /var/run/samba
        utmp directory =
        wtmp directory =
        utmp = No
        default service =
        message command =
        get quota command =
        set quota command =
        remote announce =
        remote browse sync =
        socket address = 0.0.0.0
        nmbd bind explicit broadcast = Yes
        homedir map = auto.home
        afs username map =
        afs token lifetime = 604800
        log nt token command =
        time offset = 0
        NIS homedir = No
        registry shares = No
        usershare allow guests = Yes
        usershare max shares = 100
        usershare owner only = Yes
        usershare path = /var/lib/samba/usershares
        usershare prefix allow list =
        usershare prefix deny list =
        usershare template share =
        panic action = /usr/share/samba/panic-action %d
        perfcount module =
        host msdfs = Yes
        passdb expand explicit = No
        idmap backend = tdb
        idmap alloc backend =
        idmap cache time = 604800
        idmap negative cache time = 120
        idmap uid =
        idmap gid =
        template homedir = /home/%D/%U
        template shell = /bin/false
        winbind separator = \
        winbind cache time = 300
        winbind reconnect delay = 30
        winbind enum users = No
        winbind enum groups = No
        winbind use default domain = No
        winbind trusted domains only = No
        winbind nested groups = Yes
        winbind expand groups = 1
        winbind nss info = template
        winbind refresh tickets = No
        winbind offline logon = No
        winbind normalize names = No
        winbind rpc only = No
        create krb5 conf = Yes
        comment =
        path =
        username =
        invalid users =
        valid users =
        admin users =
        read list =
        write list =
        printer admin =
        force user =
        force group =
        read only = Yes
        acl check permissions = Yes
        acl group control = No
        acl map full control = Yes
        create mask = 0744
        force create mode = 00
        security mask = 0777
        force security mode = 00
        directory mask = 0755
        force directory mode = 00
        directory security mask = 0777
        force directory security mode = 00
        force unknown acl user = No
        inherit permissions = No
        inherit acls = No
        inherit owner = No
        guest only = No
        administrative share = No
        guest ok = No
        only user = No
        hosts allow =
        hosts deny =
        allocation roundup size = 1048576
        aio read size = 0
        aio write size = 0
        aio write behind =
        ea support = No
        nt acl support = No
        profile acls = No
        map acl inherit = No
        afs share = No
        smb encrypt = auto
        block size = 1024
        change notify = Yes
        directory name cache size = 100
        kernel change notify = Yes
        max connections = 0
        min print space = 0
        strict allocate = No
        strict sync = No
        sync always = No
        use sendfile = No
        write cache size = 0
        max reported print jobs = 0
        max print jobs = 1000
        printable = No
        printing = cups
        cups options =
        print command =
        lpq command = %p
        lprm command =
        lppause command =
        lpresume command =
        queuepause command =
        queueresume command =
        printer name =
        use client driver = No
        default devmode = Yes
        force printername = No
        printjob username = %U
        default case = lower
        case sensitive = Auto
        preserve case = Yes
        short preserve case = Yes
        mangling char = ~
        hide dot files = Yes
        hide special files = No
        hide unreadable = No
        hide unwriteable files = No
        delete veto files = No
        veto files =
        hide files =
        veto oplock files =
        map archive = Yes
        map hidden = No
        map system = No
        map readonly = yes
        mangled names = Yes
        store dos attributes = No
        dmapi support = No
        browseable = Yes
        access based share enum = No
        blocking locks = Yes
        csc policy = manual
        fake oplocks = No
        locking = Yes
        oplocks = Yes
        level2 oplocks = Yes
        oplock contention limit = 2
        posix locking = Yes
        strict locking = Auto
        share modes = Yes
        dfree cache time = 0
        dfree command =
        copy =
        preexec =
        preexec close = No
        postexec =
        root preexec =
        root preexec close = No
        root postexec =
        available = Yes
        volume =
        fstype = NTFS
        set directory = No
        wide links = No
        follow symlinks = Yes
        dont descend =
        magic script =
        magic output =
        delete readonly = No
        dos filemode = No
        dos filetimes = Yes
        dos filetime resolution = No
        fake directory create times = No
        vfs objects =
        msdfs root = No
        msdfs proxy =

[printers]
        comment = All Printers
        path = /var/spool/samba
        create mask = 0700
        printable = Yes
        browseable = No

[print$]
        comment = Printer Drivers
        path = /var/lib/samba/printers

[lwf]
        comment = Test-Laufwerk
        path = /srv/samba/fdrive
        write list = @users
        force group = users
        read only = No
        create mask = 0664
        force create mode = 0664
        directory mask = 0775
        force directory mode = 0775

OS: Ubuntu 11.10
Samba: 3.5.11