We have just upgraded from GW7.0.2 (hp2 nz build) to GW8.0.0 hp1. This is
running on NW6.5 sp8.

Webaccess works perfectly from inside or network. For Internet access we
have always used an Aventail SSL appliance and through that GW7 webaccess
was faultless. With GW8 via the SSL gateway we have a few problems. Most
functions work, users can read and send emails etc. But some functions such
as delete or 'mark as un-read' just return the user to the login window. It
would seem that GW8 is using something new that the Aventail software is
unable to translate.

Can someone suggest what has changed between the 7 and 8 webacccess that
might be causing this?

Is there a way to run gw8 webaccess in a more 'gw7 webaccess' mode?
Apache/Tomcat settings perhaps?