I have configured my NW 6.0 DNS server as a Secondary to an external domain,
which is working perfectly. However I don't want to cache any entries for
the external domain. I cannot see anywhere where I can force the NW 6.0
server to either not cache the entries at all, or pull updates from a third
party primary (zone transfer) every few minutes.

What I have done instead is to set up a glue record in my existing flat
domain pointing to the external domain. This works perfectly, but again I
try changing an entry in the external domain, and that change is not
reflected straight away, which is what I desperately need. Of very close to
straight away.

I have a very large flat domain, and I don't really want to remove caching
completely, just for the external domain. Either with a glue record or a
second domain.

Help would be greatly appreciated.