Once you're a liaison, order every BSD related document you can. If you do not have the 4.4BSD book by McKusick et al. I guarantee that any pedagogically oriented professor will have a hard time presenting an argument against you if you are well prepared. Go the extra mile and print one-page handouts about where to find more information about FreeBSD, both on campus, and on the Net. And that my friends is all.
Persistence is the key.
You've got to keep nagging and prodding until FreeBSD is the OS powering your department.