I came to your article from another article and am really interested in this learning about this. , 
I feel strongly about information and love learning more on this. If possible, as you gain expertise, 
It is extremely helpful for me. would you mind updating your blog with more information?

1. I was created a root level account named backdoor on the ESXi by connecting to ESXi directly using root
2. I tested that I was able to connect directly using backdoor
3. I enabled Lock Down Mode by connecting to the vCenter
4. Once this was set, I was NOT able to connect directly to the ESXi server. Error was that I didn't have permission to log-in.
5. I was able to connect using backdoor straight to the ESXi server.
6. I then disabled Lock Down mode in vCenter.
7. I was then able to connect directly using root.

If you want me to test anything else, shoot me an e-mail.

You should look at it as managing an ESXi or ESX host through vCenter, look at it as configuring the hypervisor to make it work in your virtual infrastructure. Yes, at this point you do have think about ESXi or ESX but in later versions (ESX5) I'm convinced it all doesn't matter anymore.

Good to know though, even if it's just disabling lockdown as part of the bring up procedure.