Is it possible to insert a Vodafone SIM into the 'worldmode' Sim slot of a Samsung i325 and have it work on the GSM network.  I have a handset that is not under contract and is decomissioned on the CDMA network.  I would now like to swap the phone to the GSM network.  I have inserted a Vodafone SIM but it doesn't recognise it.  Does it need unlocking or is there a hack I could try.