I have an ECS C7VCM2 board and it has a Realtek 10/100/1000 chip on it.
When my SME server is booting up and it gets to the bringing up eth0 it says FAILED very quickly and then says OK
AFAIK this is proper behavior, can not find the reference but I have seen this myself as well.
I have no network connection to my server it will not ping nor access to the sever manager etc.
I have visited the Realtek website and downloaded a BSD Linux driver for the NIC.
As stated many times before SME Server is based in CentOS, which is based on RedHaet Enterprise Linux, which is not at all like BSD so that driver won't help you.
Compiling a driver is not the easiest task and you need to recompile with every new kernel, so I suggest to buy a supportd NIC as this is the easiest way to go (and considering the workload also the cheapest).