Hello Whoinnetooss37
Welcome to the SBB Community.
We are a customer support forum run by volunteers, not the SBB Customer Service.
The use of Halbtax PLUS for international travel is not planned as it is not part of the international tariff. Its intention is to promote the domestic public transit.
If you want to use Halbtax PLUS on international routes, you have to split the tickets just as you have to when using Saver Day Passes and similar saver offers.
Or, simply make use of an international saver ticket offer.
Kind regards,
Roland