FreeBSD 7.4-STABLE server behind an isa server

[Jack Raats]

I am setting up a FreeBSD 7.4 server behind an ISA server. The purpose of this server is to serve as an intranet web server.
But I would like to update the ports of course.
I have a login and password for the isa server.
I would like to know how to implement this so that I can usr portupgrade to update the ports and to use make install

excuses for the bad english

thanks

Jack