hi NiCad,
you can use VStank replacements so i'm told, you can also get some usefull batteries here.
http://www.people.zeelandnet.nl/ptrick
ok, ok, i ran out of them a while ago, but i'm looking for some new ones.
the type is GP11AAAM. thats 1/4 AAA cell, and that's two of them in serie.