It didn't take long time to figure out working method.
You have to follow guide precisely, otherwise it may not work!
1) download Windows XP x32 driver attached in this post.
2) Turn off your Omnia II
3) connect Omnia II to computer.
4) Go to device management console and update Samsung MITs driver with one you downloaded in (1). Make sure you didn't get error while updating driver.
5) Disconnect Omnia II from computer.
6) Grab any version of OCTANS (newer - better) and using right click menu open properties of OCTANS executable and set compatibility mode to Windows XP Service Pack 3
7) Start OCTANS and follow usual guide to flash your Omnia II.
I've tried it by myself and it's 100% working.
If it's not working for you then you did something wrong. Check my guide again more precisely and correct your mistakes.
For x64 perverts, there is X64 driver attached. Guide is exactly the same, but i didn't test it because i hate to deal with MS signature checks. Only real perverters love Windows x64 and its signature hell
X64 driver is not signed, so have a nice sex with WinX64. I know you like it