I'm afraid the you cannot mix these two models in the same cluster, i.e. use vMotion/DRS. According to the VMware Compatibility Guide, the 22xx CPU models support EVC modes "AMD Opteron™ Generation 1,AMD Opteron™ Generation 2", whereas the 62xx CPU supports "AMD Opteron™ Generation 3 without 3DNow!,AMD Opteron™ Generation 4"
André