If you add the drive to the server's storage pool then no, Windows Home Server won't expose the drive for you to address directly. If you want to protect your data against the failure of a drive in your server, turn on duplication for all your shares. You will be able to access your data in any event, as the files that are on the individual drives in the storage pool
are accessible by connecting the drive(s) to another PC and copying them. See
this FAQ for more information about that.
I'm not on the WHS team, I just post a lot. :)