Or you could purchase the #675 adapter I've made for years and support an APUG member at the same time: http://rick_oleson.tripod.com/index-111.html (you can see it midway down on my friend Rick Oleson's page). Unlike the slip-on washer approach, mine will place the zinc-air cell at the proper height every time. It is still $14 and that includes free shipping to anywhere and a lifetime guarantee. A small 100% neoprene ring keeps the cell centered in the adapter and the design prevents any damage to your camera from a malfunction of the zinc-air cell. Also, unlike the adapter mentioned above, mine is guaranteed to be infinitely stackable (try to stack Wein cells or the battery adapter above...you'll discover the top cell will be intermittent at best and may not work at all).
Please email me at jon_goodman@yahoo.com if you're interested.