wiring colours for replacement seatbelt

Help my son has a 2000 year 3 door micra 1.0 sport the f/n/s seatbelt recently broke and i have sourced a replacement unfortunately the wiring for the pre tensioner is different , there are 2 wires to the old units pre tensioner 1 green and 1 brown. the replacement unit also has 2 wires one green/ black and 1 coloured purple/yellow the question is does any body know what wire connects to what or is it possible to remove the plug from the end of the pretensioner. The vehicle is a uk vehicle