Amit, why not get a NetGear RND 2000 and have peace of mind. I am not affiliated with NetGear, but have used their products for long and they continue to dazzle me years after years. I wouldn't skimp on loose change for something as important as a storage device.
NetGear RND 2000 supports SBS officially, and has firmware available.
Just to logically close this thread, I installed Arch linux on Go Flex Home. It tool all of 20 minutes. File transfer speeds are now in > 30 MB/sec. Squeeze center yet to be installed, will try doing on weekend.
Other than a few supported versions SBS will need to be compiled on the OS.
To tinker with OS of your NAS , is playing with fire. It may just brick the device.
WD NAS is a ARM device , so there should be flavor of Debian / Arch for it. Debian is better since you can possibly get binary SBS on it.