Active Directory Authentication via Host profile

I am trying to use apply a host profile via powershell script that will add an esxi host to my active directory domain. 

$vCenter = Read-Host "Enter vCenter"

$esxhost = Read-Host "Enter FQDN of the ESXi host"

$ADdomaincreds = $host.ui.PromptForCredential("Enter Credentials", "Please enter your Active Directory username and password.", "", "")

$hostprofile = Read-Host "Enter HostProfile to apply"

#CONVERT SECURESTRING

$CONVERT_AD_PASSWORD = http://System.Runtime.InteropServices.Marshal::SecureStringToBSTR($ADdomaincreds.Password)

$AD_PASSWORD = http://System.Runtime.InteropServices.Marshal::PtrToStringAuto($CONVERT_AD_PASSWORD)

Connect-VIServer $vCenter

$hostprof = Get-VMHostprofile -Name $hostprofile

$applyhost = Get-VMHost $esxhost

Set-VMHost -VMHost $applyhost -State "maintenance"

$additionalConfiguration = Apply-VMHostProfile -ApplyOnly -Profile $hostprof -Entity $applyhost -Confirm:$false

$additionalConfiguration = $ADdomaincreds.username

$additionalConfiguration=  $AD_PASSWORD

$additionalConfiguration = Apply-VMHostProfile -Profile $hostprof -Entity $applyhost -Variable $additionalConfiguration -Confirm:$false

It runs with no errors but when I look at the esxi host it still says it is using Local Authentication.  If I apply the host profile via the VI Client, it works with no issue. Is there anything else I need to set in the variable?

I have also tried using LucD's Set-VMHostADDomain function.  That works, however, if I then apply my host profile to finish configuring the other components such as syslog, ntp, etc, the authentication gets reset to local authentication after a reboot.