OPENCART payments per product fix required

Hello people, i'm looking for an Opencart expert for payments per product function fix on my customized ecommerce site. These are requirements: 1) PAYMENTS PER PRODUCT (ADMIN SIDE) Previously i was able to select one or more payments enable for each product and save them. Check payments tab on product page (admin side). By default when a new product is created all payments are enabled and checked but if i try to deselect one or more flags and save the product automatically all flags are removed and related records on product_to_payment table are deleted. Another issue appears on product page (admin side) after making modifications on payments tab: save and continue button stops to work (you are redirected to product list page and not to opened product page). I need to fix that issue and proceed to point 2. 2) ALLOWED PAYMENTS ON CART FIX (maybe not necessary after point 1 fix because it worked on past) During checkout we system must show only COMMON enabled payments of products on cart. For instance: PRODUCT 1 - Allowed payments: ALL PRODUCT 2 - Allowed payments: PAYPAL and BANK TRANSFER PRODUCT 3 - Allowed payments: PAYPAL, BANK TRANFER and COD System will show on checkout payment page : PAYPAL and BANK TRANSFER DO NOT PLACE BIDS OUT OF BUDGET!!! PLEASE READ CAREFULLY ALL REQUESTS AND POST YOUR BID ONLY IF YOU ARE ABLE TO MANAGE AND COMPLETE THE PROJECT. Payment details : 100% milestone at project start. Milestone release will be completed ONLY when you will get my complete satisfaction.