You possibly need something like this then as well
http://www.rcaccessory.com/evpxh6s.aspx
Looking at some of the places selling that particular charger, it looks like it should have come with one.
I've used this company before with no problems and they seem to have a variety of things. Something might be suitable:
http://robotbirds.com/catalog/index.php?cPath=9_187_276