E-purse concept in smart card

Question

Hi,

 

 i'm currently working in smart card development project. This smart card is used for purchase any items from some shop that shop will  be permitted for government. In this project i have completed the read and write user details into smart card using READ BINARY and WRITE BINARY command. now i need to how to load the money into smart card, how can i use that smart card into E-Purse? if any one have a solution help me..