Mountain Lion forgets workgroup name after every reboot

Mountain Lion seems to forget its WORKGROUP settings (Network Settings/Advanced/WINS) with every reboot, which breaks SMB file sharing for my Windows PC. Every time I restart my MacBook, I cannot access the SMB shares on this Macbook from my PC until I go to Network Settings on my MacBook and re-enter the workgroup name, which miraculously disappears with every reboot. This problem started to happen with Lion, and still persist in Mountain Lion; Everything was working fine in Snow Leopard. I've done a clean installation of Lion and Mountain Lion multiple times, to no avail.

Apparently I'm not the only user affected by this, and according to other forum discussions I found on the internet (e.g. http://www.insanelymac.com/forum/topic/267663-lion-and-smb-workgroup-problem/) the only reliable solution would be to disable Apple's buggy SMB file sharing and install samba3. I'm reluctant to go down that road because I don't know how what other implications this might have/how this could affect future OS updates/network security, etc.

The MacBook Pro in question is no longer covered by Apple Care. What are my options at this point? How can I make Apple aware of the problem? Did somebody find a less complicated and less intrusive workaround/fix?

Thanks,

George