technical problem:common app letter of rec...

hello guys,im from taiwan, i intend to apply in some u.s universities,but i got a huge problem,my high school teachers dont have emails under the name of the high school site(example: jh@high-schoolname.com),neither does it has ceeb code,my question is how should i convince the admission committees that these emails are valid and belong to my teachers?how can i prove them that i am not lying?
how do they trust my teachers as my real teachers who taught me,do they call them? i can ask them to write the letters on some papers then sign and seal them and scan them and send them via email.does it work?
so what is your advice?

Email the admissions offices at the schools you are applying to and ask how they would prefer you send the letters of rec.