Netmap and Hotspot

I am trying to map all hotspot users to a range of public ips and it all seems to be working except for http traffic (which looks like it is coming from 1 ip address regardless of the hotspot user) - any idea what is going on? I am assuming that I need to bypass the proxy server somehow but have been unable to figure out exactly what to do..

If it’s not that then I would appreciate any light anyone could share on the subject!

Thanks

Paul