Sage 200 Manufacturing MRP Build - Returns

The current MRP build ignores returns and does not include these in the stock projections Our end user would like the option to include both purchase and sales returns purchase returns are the most import , example given, received 80 of the item, but raised a return to send 60 back,...cannot despatch out yet as waiting suppliers returns number, but also cannot use If they had a tick box where these could be included in the MRP build same as it does for sales orders/purchase orders