Those are the exact reasons why many colleges still don't accept ASL as a foreign language. Even if they do accept it as a language and not a dialect of English, there is the notion that there isn't a culture associated with it. This was the case for many years at the school where I went through my ITP, although they finally turned around on the issue (as more and more schools are).
I would say collect as many resources as you can to show that there is a culture associated with ASL. "Into the Deaf-World" by Lane, Hoffmeister, and Bahan is a good book for this purpose. Write a persuasive report, citing your references, and submit it to whoever is in charge of these things.