Anyhow I made it work for EPU-4, and following is the tutorial.
1) Download the EPU-4 installer from ASUS website.
2) Extract the zip file and go to "Io" folder and run AsIoIns.exe as administrator in compatibility mode for Windows 98 / ME. To be sure it installed proper driver you can also run it in compatibility mode for Windows 7.
3) From Acpi64 folder (Acpi for x32 windows version) run AsAcpiIns.exe in compatibility mode for Windows 98 and then for Windows 7 as administrator.
4) Restart the PC.
5) Run Setup.exe from the parent folder as administrator in compatibility mode for Windows 98 / ME (all other options will end up with failure). A restart prompt will appear so restart your system.
6) Copy AsIO.dll, AsIO.VXD, AsIO32.sys and AsIO64.sys from "Io" folder to C:\Windows\System32 folder.
After windows restart you should have working Epu-4 Engine. Overclocking, declocking and especially fans speed control works very well.
For installation of EPU-6 Engine, there is a great tutorial here.