Balance 380 and Secondary DNS

I am setting up one Balance 380 for a client.

He has 3 different ISPs, three sets of associated static IP’s.
I am changing his NS records to point to the IP’s associated with each of the three ISP’s. NS1, NS2 and NS3.
I like to setup backup NS with DynDNS secondary DNS service.

I was curious if anyone has had challenges with having the 380 do zone transfers to DynDNS DNS servers.

My goal is to have backup DNS service in case the Balance 380 goes down.

Thank you,

Balance 380 support zone transfer that allows 3rd party DNS server to obtain the latest DNS records from Balance unit. If DynDNS supports zone transfer, then it should able to get the DNS records from the Balance.