Thanks for the reply.
I know what you mean, but I would need to change complex .sql in my download centre in order to make that work. Because currently it filters weather the item has a value in the product location field or is NULL.
I was hoping I could just make the file field allow a NULL value to be created in the database.
It works for my image uploads. I think that is because they are set up to only allow web images.
However I would of thought that this should not be that hard to do?