NIC detection happens at install stage, so unless the third NIC is the same as one of the existing two (thus uses the same module) you will have to either manually edit the necessary configuration files to load the module (maybe something like /etc/module.conf), or re-install. I think the best option is just to use the same card as one that is already in there. Worked for me. As the other guy said, reinstalling and re-configuration is so easy though...
NIC detection happens at install stage, so unless the third NIC is the same as one of the existing two (thus uses the same module) you will have to either manually edit the necessary configuration files to load the module (maybe something like /etc/module.conf), or re-install. I think the best option is just to use the same card as one that is already in there. Worked for me. As the other guy said, reinstalling and re-configuration is so easy though...