Comment 6 for bug 657183

I don't fully understand the code, which I think could use some refactoring, but the reason I didn't just modify GET-EXTERNAL-FORMAT is that I believe that :DEFAULT means something special only if the ELEMENT-TYPE is CHARACTER, so GET-EXTERNAL-FORMAT would need a second argument (possible &OPTIONAL) to make sure it doesn't do anything silly when the ELEMENT-TYPE is (UNSIGNED-BYTE 8) or something.