You will need to open up the firewall between your server and the update point for the ports your are using. 80, 8081, 443 if you are running at the defaults. If you changed these settings (which you should have) then use your values.
ok - so here's how you do it.
Export the master respository key from the main server, and import it into the second server. Walla!
There is a KB somewhere on Mcafee about using two EPO's to control repositories.
I worked out how to do it! Mcafee Gold support were wrong btw.