I am attempting to hard code the scsi0:0 disk to persistent mode. I can manually enter Name scsi0:0.mode and Value persistent into the Advanced Config setting and things work great. If I attempt to use the new-advancedsetting -entity $vmguest -Name scsi0:0.mode -Value persistent the value never shows up in the GUI and upon subsequent runs keeps asking if I want to create. Can anyone confirm this or point me in the right direction??
First of all, why don't you set this setting through the Set-HardDisk cmdlet? See: http://www.vmware.com/support/developer/PowerCLI/PowerCLI51/html/Set-HardDisk.html
Did you check whether the value is actually present in the VMX file afterwards? Try a ReloadVM task to refresh the settings displayed on the GUI:
($vm | Get-View).Reload()
You probably can only set this on a powered-off VM too.
By setting the scsi0:0.mode it overrides what the Set-HardDisk setting does. Effectively you can hard code the scsci0:0.mode to persistent and use the Set-HardDisk to set it to Independant non-persistant and the drive will still commit all changes immediately.