There are a couple options to your question.  You could duplicate your full
backups to empty tapes which you move offsite (ie have a volume pool
set up for just offsite storage, then if you eject the tapes after the
duplications, you'll only have empty tapes in the pool).  Or you could
just backup to an offsite volume pool (set up the same way).

For the second question, if you use different retention levels for
your fulls and your incrementals they won't mix on a tape (assuming Sat is 
full, and Sun-Fri are incrementals) unless you've overriden that in bp.conf.
If you have to have the same rentention levels, then use different volume
pools for your fulls and your incrementals.

>Hello,
>
>We are using the NetBackup DataCenter to do daily incremental and weekly
>full backups. Now we want to store the weekly full backups off site. How do
>I assign an empty tape every week to be used for the weekly full backup so
>it won't have images from other backup sessions? Another question is how to
>prevent other backup sessions to write images to this tape? For example, I
>will get the tape of last Saturday's full backup this Tuesday, but I do not
>want Sunday, Monday's backup images to be written on that tape.
>
>Your help is greatly appreciated.

-- 
Jeff Bryer                              bryer AT sfu DOT ca
Systems Administrator                   (604) 291-4935
Academic Computing, Simon Fraser University