How can I enter the component twice in the BOM

I need to create a workaround in Work in Process

I have a finished item A

item A is from Item B and item B

so qty one item of A = qty one of item B + qty 2 on item B

I am creating a workaround in Worp in process

1 - How can I do that?

2 - I am not able to create the BOM with the same component twice I am getting an error

so go to BOM screen try to create a new BOM item, enter the component the first line, and enter the same component the second line not able to do that and I am getting an error