Apr 14, 2012 - 1:51 PM
In addition to my previous post:
During the proces of ordering your ticket for the train that leaves at 22.40 you'll see step 2. Passengers and Reduction for Switzerland.
Here you'll have to enter GA 2 cl 1 year/GA subscription or GA 1 cl 1 year/GA subscription (depending on the class you have your Swiss Pass for).
The GA (General Abonnement) is equal to your Swiss Pass and the Swiss leg of your journey will automatically be deducted from the total fare.