If UltraDNS is being used as a Secondary DNS provider and the Primary zone has DNSSEC enabled, UltraDNS will serve queries for the secondary zone so long the account where the secondary zone will be hosted has DNSSEC enabled.
To confirm this, the Domain will have a DNSSEC tab between the Properties and Zone Transfer tab:
If you do not see this, contact support to have DNSSEC enabled for your account. Once DNSSEC is enabled, then you can setup the zone as Secondary on UltraDNS: