In my peugeots the pretensioners are in the bit you clip the belt into. they have a little pyrotechnic charge that pulls them down locking the belt. Are others build into the reels themselves?
If so then i would check you have the radio code and then disconnect the battery and leave it for half and hour to an hour before you disconnect anything but it is best to check this with your manufacturer or someone who has access to the repair procedures.
In all honesty my pretensioner wires have come undone under the seat and flagged a fault so I have just turned the ignition off and reconnected them with no harm (not fired or caused a permanent fault) but it's probably best to follow procedure as you don't want to be fishing around to replace the airbag ECU or going to get the one in the car reset.