Ignition barrel change

Hi. Could anyone give me some advice on changing my ignition barrel. In short, my transponder key broke in the barrel and I was advised to get a new barrel with a key, which i duely did. Asking for a 1998/2004 barrel for my Discovery 2 ib an 02 plate I thought it would be straight forward. It isn't! The wiring connections from the disco don't fully match the replacement barrel. Am I missing something or is there a simple explanation? Any help would be appreciated. Cheers

was the barrel from a reliable supplier? ... i saw cases when they mixed things and sent the wrong part, the ignition barrel/switch is the same for all D2s , is it looking exactly like the one in the pic here http://www.island-4x4.co.uk/steering-lock-ignition-switch-discovery-economy-d2lock-p-2496.html