Sub-domains do not work.

[othellotech]

Since the server in question does not manage it's own DNS, modifying through WHM etc would not have any effect. The modification needed to be done on a DNS level (one of our dns machines) so that the internet knew where to go with the subdomain.

What you need is a centralised authoritive DNS cluster that can pull all the zone details from your own and client machines ... like the one we have