7912 not downloading gk file

I got couple of 7912 and I flashed sip firmware on the phones. The phones load gkdefault.cfg fine but I can’t get them to load gk files with mac addresses.
the phones will load all configuration settings from file as long its name is gkdefault.cfg How I can get phones to load they configuration files ?

Make sure that your “Profile Encrypt Key” is set to “0”

ref:-

http://www.voip-info.org/wiki/view/Cisco+7905/7912+IP+Phones

I found this website and I guess the gkmac file can’t have cfg at the end.
http://wiki.val.bmstu.ru/doku.php?id=cisco_7912
Is there a way to use that phone for pages ?