Using the duchess in trainz 12

I have the Duchess add on pack and I have been using it in Trainz 2010 with no problems. I have recently brought Trainx 2012 (10th anniversary edition) and I would like to use the Duchess in Trainz 2012. Any idea how I would do this? Do I need to re-enter the serial code and, if so, where?

EDIT: Don't worry. Problem sorted