If students are taking a VHS class not being taught by one of their teachers, they DO need to have a record in SCS for the student, but DO NOT need a corresponding record in EPIMS (staff roster or work assignment). In this case, set the FTE to zero in the teacher's work assignment and do not include zero FTE's in your EPIMS export. This will create the student course record, but no corresponding teacher work assignment record.
If a district teacher is actually teaching a VHS course, then yes, an EPIMS record would be required and the appropriate FTE value should be entered and included in the export.