I unlocked my Samsung v804SS (Japan) without usb cables and it now works on all networks. It was really easy and using cables is certainly not recommended.
My sister is going to Japan and she wanted to use my cell phone with her SIM card as I no longer pay monthly fees to Vodafone (now Softbank). So, I unlocked the phone so that she may use her card.
I tested everthing and it wors fine. The only problem was that the phone seemed to work a little slower, but then again that could be me.
I have the code to unlock and lock all v804SS phones