a) Go to ""Device Admin", select "Web Management" and uncheck the "Enable" SSL box or...
This option will disable ssl access for the entire firewall. The ssl mgmt service will no longer be available at all.
You use this option if you don't want ssl available at all on the firewall.
b)Uncheck the SSL box on every firewall interface/sub-interface?
This option controls which interfaces will accept ssl connections. The ssl mgmt service is running but will only listen for connection on the interfaces that have the ssl box enabled.
Use this option if you want to turn off ssl on the edge interfaces but leave the ssl available to your internal network interfaces.