Have you tried the new SetOption() options?

From the KiXtart docs:
Wow64FileRedirection ON,OFF Enables/disables file redirection on 64-bit editions of Windows.
This option has no effect on 32-bit editions of Windows.

WOW64AlternateRegView ON,OFF Enables access to the alternate view of the registry.
This option has no effect on 32-bit editions of Windows.