[Samba] DNS update won't work with samba4

[polytex polytexx]

Hi,
I installed samba4 with bind 9.7.2 but my dns updates have not working
correctly. It would really help full if some of you could help me.
configuration as follows

installed according to Samba4 how to URL(
https://wiki.samba.org/index.php/Samba4/HOWTO).
bind compiled with following options

./configure --with-gssapi
===========================================================
named.conf

        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
        recursion no;
        tkey-gssapi-credential "DNS/tfc.lk";
        tkey-domain "TFC.LK";

        dnssec-enable yes;
        dnssec-validation yes;
        dnssec-lookaside auto;

        /* Path to ISC DLV key */
        bindkeys-file "/etc/named.iscdlv.key";
............
............

include "/etc/named-samba.conf";
=====================================================================

named-samba.conf
...............
...............
zone "tfc.lk." IN {
        type master;
        file "/var/named/dynamic/tfc.lk.zone";
        include "/usr/local/samba/private/named.conf.update";


zone "175.168.192.in-addr.arpa" in {
        type master;
        file "175.168.192.in-addr.arpa.zone";
        update-policy {
                grant *.LK wildcard *.175.168.192.in-addr.arpa. PTR;
...................
...................


on a Linux system (Linux Mint 10 Julia).  The configure/make/make
install seems to run fine. I didn't see any error messages related to
gssapi (configure finds the libraries and header files without
problems.)

Thanks in advance,
PTX.