To save seeds over time, in the end you have to plant them and
collect the next seasons seeds. It's the only way with seeds that
aren't viable for long. I do a search on 'seedsavers' 'seed banks'
and see what comes up. There are groups around the world who do just
that to keep species alive.
And lo and behold, a nice .edu site :-)

http://csf.colorado.edu/perma/stse/handbook.htm
http://csf.colorado.edu/perma/stse/store.htm

http://homepage.tinet.ie/~merlyn/seedsaving.html

--
Cheers,
Loki [ Brevity is the soul of wit. W.Shakespeare ]