Galaxy S locked to carrier...no code requested..?

Ok here we go, I've got an Oputs locked Galaxy S, I just wanted to unlock it to other networks so I can use a Vodafone Sim to talk for free with my girlfriend.
I've tried to follow this simple steps from the xda's (http://forum.xda-developers.com/showthread.php?t=761045)
to get my unlock code, but when it comes to this:

Cit. "Power down your phone
Put in a SIM card from another carrier
Power up your phone
When it boots up it will ask for the unlock code that you found above"

I power it up with the other SIM it doesn't ask me for any code, I got Vodafone reception, but Data Network errors and call barrings activated both for incoming and outgoing....so pretty much useless!
any idea where to put in this code, or any other suggestions on how to get my Galaxy free of his chains?

Thanks everyone!!

Hi, i think you are not following the instruciton...ok .you can get the unlocking instruction at Superunlockcodes . this is basically a unlock code provider, don't worry about that. you click the link "Supported Phones" in the website and then select your phone make , model and network , then you will get code price, and below that you can the instruction. you take the instruction alone and enter the unlock code as per the instruction . if you furthermore couldn't unlock , your unlock code may be a wrong one, if this is your case, you can get the correct unlock code at the website i have mentioned above..