Just an update on this thread:
After a hard work digging the internet, I found a blog informing that the patch kit 5.1.2a should fix the "vmknic not created" issue.
Donwload link: https://my.vmware.com/group/vmware/details?downloadGroup=VSP51-VCL-VCNS512A&productId=286&rPId=3347#errorCheckDiv
However, I am not able to get it. VMWare page returns "We are activating your licensing key entitlement, re-try your download soon".
Once I purchased a trial version of vShield 5.1.2, is there an easy way to get the 5.1.2a patch kit file?