Hotspot problem with DNS

Hi Gurus,

Can anybody explain how the hotspot plugin in an AP deals with DNS. and possibly offer a solution to my problem?

From what I can work out, the Hotspot plugin causes the AP to become a DNS proxy and all DNS requests are redirected to the proxy by the firewall and Nat rules added by the plugin.

I understand this is necessary to make the Hotspot authentication system work.

My Problem,
I want to be able to force a single user to a different DNS server after authentication has succeeded rather than continue to use the AP as DNS proxy as currently happens.

Looking forward to hearing any ideas