Been looking at vista pe. Themes work after switching to admin. No patching required.
Just like this using pemd load switch.ini
switch.ini
EXEC !=%SystemRoot%\System32\tsdiscon.exe
WAIT 10000
REGI HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\ForceAutoLogon=0
Relaunch explorer as admin using pecmd load sys.ini
sys.ini
exec !%windir%\system32\tskill explorer
exec %windir%\system32\psexec -i -d -s explorer