He would cast a ritual, allowing him to automatically succeed at passing that particular border (or possibly that sort of border) for the duration of the spell. This seems like a simple application of 'improbable actions' or 'skill replacement'. The first works best with a single action duration ritual that is cast each time and should be on the order of power/complexity 4. The second would need a power/complexity equal to the border rating plus the steps up the time chart from one scene (basically, how often he needs to redo the ritual).
The other way to do it is for him to create and maintain the border in the first place, but thats back to the wards mechanics.