I have a hidden master with the following SOA:
bellgrim.se. 300 IN SOA sanjose.bellgrim.se. rickard.bellgrim.se. 2011032195 90 30 140 360
I start the Signer Engine. Let it fetch the zone, then stop the hidden master. OpenDNSSEC should then stop serving the zone, because we eventually pass the SOA Expire timer. But it still answers to DNS queries.