Dear Unchalee,
I think we cannot use automatic posting in this case, because it is ompossible to respect your rules for currency conversion.
The reason is that when we post the I/C invoices in your Accounts Payables, the system doesn't know the custom clearing date and is not able to use this date to convert the foreign currency into Bath.
Our proposal is to block this automatic posting and ask you to post I/C invoices manually.
Let us know you comments, please
Ciao, kind regards