Unable to add an catalog Item to cart in iprocurement

Hi Folks,

i'm unable to add an catalog Item to cart in iprocurement. Below are the steps i have followed

1. created browsing category and item category underneath it.
2. done with mapping from purchasing category to shopping category.
3. created a store having content zone assigned to a responsibility and chose the category.
4. created an item from inventory super user (having organization access for which i had created an item) and under "purchasing" tab i did checked the checkboxes "Purchased" and "Purchasable" also entered the value in " List Price" .
5. Item has been assigned to purchasing category from "Tools-->Categories"
6. from the iprocurement responsibility i can able to see the store which i have assigned and browsing category, item category and finally an item.