This o­ne's in English:

http://www.vodafone.jp/english/release/2004/040506e.pdf [1]

A bit different from DoCoMo's contactless smart card (Felica) I believe. The vodafone version has been jointly developed with Sharp, and uses a flash memory card plugged into the slot o­n the phone to achieve these capabilities.
Backwards compatibility, anyone? It would be nice if users could simply plug a flash memory card into their phone and have it able to use smart card services, but something tells me there's more to it than that.