How to add custom post type to item blog select, now show all categories but only work the normal entries not custom post type,
What you ask for requires file customization that is not allowed in reference to the Item Support Policy. http://themeforest.net/page/item_support_policy
So if you want to modify files and don't know how, you should contact your web developer. Item Policy says:
Item support does not include services to modify or extend the item beyond the original features, style, and functionality described on the item page. For customization services that will help you tailor the item to your specific requirements, we recommend contacting the author to see if they privately offer paid customization services or checking out the great service providers on Envato Studio.