Questions about public transport certificate, internships

I want to apply for an NMBS campus card or school season ticket and I need proof of registration:

To apply for a campus card or school season ticket from the NMBS, you can download a proof of study via your SisA selfservice. You must enclose this proof with your application. The proof must not have an original signature or stamp. The registrar's office also does not fill in NMBS forms.

ATTENTION! For INTERNSHIPS: public transport certificates for a different route (i.e. not place of residence/university) must be requested via fswhelp.be stating the route and the period.