can i update billofexchange's child data using DI Object "BillOfExchange"

Hi,

I want to update billofexchange's child data.

Table id is "BOE1"

So, oIncommingpayments and oVendorpayments have billofexchage member.

But, it hav't any "lines" member.

How can i update child data (BOE1 table)?

Thanks in advance.