Maya 8 is virtually incompatable with anything used in Maya 7 at the moment. Alias has to make more stuff so that you can use your old renderfarm. So, most things aren't exportable with Maya8 either. In my opinion, Maya 8 is unnecessary and is barely any different than Maya 7. So, I guess you'll have to wait for a plug-in or something.
You'll also notice that art done in Maya 8 can't be taken to Maya 7.
"The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man."
George Bernard Shaw - Man and Superman