You are correct....Offline Jumpseaters are not allowed to occupy the actual JS, but are allowed to be a "jumpseater" while occupying an available seat in the passenger cabin....this is true on Int'l flights. We just had this case last month and were able to look it up in the ops manual and it states this very clearly. If you have any problems at the gate, try and speak in the Captain directly if possible. I'm sure he or she will help out the best they can.

If there are any departure taxes from the place you are departing, you will have to pay them as a regular passenger, but they should be nominal at best.

Good luck.