BOM - Component Stock Requirements for BOM that cannot be built

Have tried multiple ways to find out what components are needed for BOM and have spoken to our support. i.e I have a component that is mainly used on BOM but I cannot find out how many I need to fulfil these orders. I can find ones that are allocated - obviously because we have stock. I can find PO's the components are on but not the Sales Orders that they are on because they are part of BOM that cannot be built because we do not have stock. So frustrating. I just want to find out what components we need for which BOMs, on a report that just says stock required to fulfil BOMs.