repopulating cleaned ddns zone

[Brian J. Murrell]

I have a 4.1.1 dhcp server configured to update a bind9 server with ddns 
using:

ddns-update-style interim;

I had to reset the zone that all of the currently outstanding leases are 
in.  I thought that the next time a lease is updated it will just re-add 
the record and soon enough the zone will be repopulated.  Seems I was 
wrong about that.  I am guessing the dhcp server is making some kind of 
"I've already done that so I don't need to do it again" kind of decision 
based on having added a record before.

Is there any way I can force either a complete repopulation of the ddns 
zone from the existing leases or at least force the next renewal of each 
lease to re-populate the zone?

Cheers,
b.