The black line is where is used to be but now I don't know how far to lengthen it.
The pins are sheared already, so I would use a small drill bit to get the outer pieces of the pins out of the shaft. Don't drill all the way through to the inner shaft, just enough to get the little outer plugs out. Then you'll be able to see spots where the inner part of the pins were when you slide the inner shaft back and forth. Line up the inner pins with the outer holes and you're set.
As far as connecting the shafts again, just keep in mind that you want the shaft to collapse in case of an accident, so don't use anything too tough.