Any active SIM card will activate a factory or IMEI-unlocked iPhone. However, this is a 3GS that was unlocked with ultrasn0w, which does require hacktivation if you don't have an active SIM for the original carrier. He might not have a SIM card for Vodafone.
The baseband that comes with the firmware version you just installed is not unlockable with ultrasn0w. You have a few options:
1. Install the iPad baseband (6.15.00) and then use ultasn0w.
2. Have your carrier unlock it.
3. Buy a permanent IMEI unlock online (if you can find one that's legit).
4. Sell this iPhone and buy one that is already permanently unlocked.