Чтобы при установке создавался каталог %systemdrive%\temp можно создать его в $OEM$\$1
Т.е. нужно создать каталог $OEM$\$1\Temp
Код:

[HKEY_CURRENT_USER\Environment]
"TEMP"=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,44,00,72,00,69,00,76,\
00,65,00,25,00,5c,00,54,00,65,00,6d,00,70,00,00,00
"TMP"=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,44,00,72,00,69,00,76,00,\
65,00,25,00,5c,00,54,00,65,00,6d,00,70,00,00,00
[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\Environment]
"TEMP"=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,44,00,72,00,69,00,76,\
00,65,00,25,00,5c,00,54,00,65,00,6d,00,70,00,00,00
"TMP"=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,44,00,72,00,69,00,76,00,\
65,00,25,00,5c,00,54,00,65,00,6d,00,70,00,00,00