Oracle OKS contract migration from 11i to R12, how to create contract with status billed

hi,

I am working on OKS contract migration from 11i to R12 to transfer around 500 active or signed contracts.

I can create all the contract headers, lines, sublines and billing information but I don't know how to declare the contract as billed, I find nothing under the API and when I populate date_completed at level_element level,(as discribed in some documentations), it is not sufficient, the billed amount is still displayed to 0 at all billing level.

I need help to understand how to change the contract billed information.

thanks in advance.