Technically there is no difference between an cable advertised as being SATA II and one advertised as being SATA III. There is only one international standard. Consider it an advertising gimmick.
SATA III ssd's are backward compatible with motherboards having only SATA II capabilities. That should not be a problem either.
Do you mean the motherboard's System Bios does not detect the ssd or do you mean Microsoft Windows 7 does not detect the drive?