Scrap in production

I have production of metal elements. In every production order, I have the scrap output and this is my problem.

I know, in NAV exist scrap evidency, but it doesn't work as I want. I want to have inventory evidence for scrap, because I need to sell metal scrap.

I need to post scrap output per production order. I use FIFO costing method for goods and I want that scrap have 0,00 cost, because I want to all production order cost go to main goods, not to scrap.

I want only material evidency (no cost, only quantity) for scrap because I want to sell it.

Any idea?