Maagento 1.9 - Add a product description field for front end seller

READ FIRST, BID LATER We have a customized multi vendor magento 1.9 installation based on webkul. There are two tabs to display products details on product page. Check link - [login to view URL] This works fine for admins as there are 2 fields in back-end for description. But when a sellers add products from front end, only one product details field is available to them to input. SO the other tab on product page remains undefined. Check - [login to view URL] I need a new field in the front end for sellers when adding or editing products and map it to "Art Details" tab on the product page. Any agreed upon sum will be released IF AND ONLY IF the project is completed as per the requirements, on time. NO PARTIAL AMOUNT FOR EFFORT OR TIME.