Change quantity of component while reading BOM in COR1

Hi,

is there some kind of exit or BAdI that allows to change quantity of some components automatically while creating the process order in COR1?
For example I want to make check for some components in 'materials' tab and change quantity in some of them automatically when they are taken from BOM.

I know that there is BAdI WORKORDER_UPDATE but it's disallowed to change quantity in method BEFORE_UPDATE.

Regards.