Has anyone else had problems delegating a .com.au domain name to one of Alabanza's virtual nameservers?

[Begin Technogeek Talk]
What appears to be the problem (in my case at least), is that the zone file of the secondary nameserver is incosistent with the zone file of the primary.

dig soa [primary ns ip] @[secondary ns ip]
shows as:
SOA NS.domain.com.au. hostmaster.domain.com.au

Which is good. But:

dig soa [secondary ns ip] @[primary ns ip]
shows as:
SOA ns.myupstream.com. hostmaster.myupstream.com.

This is causing Internet Names Australia to reject all delegation requests.
[/End Technogeek Talk]

If anyone else has encountered this problem before I'd love to hear how it was resolved.

James