isc dhcpd: update-static-leases not working

I am using SuSE 8.1 with isc dhcpd version 3.0.1rc9-59 and a bind DNS
server in a DDNS configuration.
Everything works fine, except the system seems to ignore
update-static-leases on;
in dhcpd.conf.
Any ideas how to solve this problem ?

Thanks Mark



Mark Dammer