[Plugin: wpStoreCart] product variations for customer input fields.

I want to use your plugin to sell phone unlock codes, so after reading the documentation I didn’t get anywhere I can allow my customers to add input field where they can select country,network provider & input field where they can type their imei of their phones with as to go with the order.
How can these product variations be added sir, reply needed urgently,thanks

http://ww.wp.xz.cn/extend/plugins/wpstorecart/