you can store them for a while in slightly moist vermiculite, but no need to refrigerate them right away... room temperature would be fine. it really depends on your time frame. when do you expect to trade them? john dudley's system works really well for speeding germination and getting high rates.

one more thing. even if you store them dry and keep them in a cool dark area they will be ok. fresh seed is best but the notion that they must never dry out is not true from my (and others) experience.

I store my fresh harvest in a damp soil less germination mix. I do not like small plastic bags, but generally use a sandwich bag. I like the Fafard super fine germination mix but have used vermiculite, washed coarse sand (concrete sand) and even have just used the soil from beneath the hellebore.

The media you use for seed storage is probably less important than the moisture level. I like the moisture level to be damp, not soggy. The media should not have any fertilizer mixed in.

The seed and media should not be placed in the refrigerator, but kept in a cool room at a moderate temperature.

I have kept seed stored in damp media for 12 weeks and longer.

Bruce

I plant fresh seeds about now in a flat with a 1/2 " mesh fence crimped down over the top and sides, and keep moist through winter. Next March or so germination begins.