How to create reseller with shared ip.

[Alexk]

I mean:

ns1.hosterdomain.com [IP - 222.22.22.22]
ns2.hosterdomain.com [IP - 222.22.22.23]

How create reseller with his ns (ns1.clientdomain.com, ns2.clientdomain.com) without an additional IP?

Should be:

ns1.clientdomain.com [IP - 222.22.22.22]
ns2.clientdomain.com [IP - 222.22.22.23]

Thanks!