NFS problem in Fedora Core 4

Hi all,
I'm experiencing a problem with Fedora Core 4, by which I don't know how to export a directory exclusively in NFSv3.
I have two raid arrays "/dev/md0" and "/dev/md1" both to be visible to SGI machines via NFSv3...
My situation is that Fedora runs NFSv4 and that causes problems with the SGI's not being able to access the arrays.
I'd greatly appreciate any advice as to how to export those arrays as NFSv3.
I realize this is a relatively slight matter for the experienced user, but alas, I am just a newbie.
Thanks ahead of time for any and all help!
-Joe