R12.1.3 - Primary and secondary ledgers in different functional currency, Tax book asset cost exchan

We are on R12.1.3. We have our primary and secondary ledgers with different functional currency. We want to know if the asset copied from the corporate book associated to primary ledger to the tax book associated with the secondary ledger will be automatically converted into the functional currency of the secondary ledger. If not, then what needs to be done to do the conversion? If yes, how does the conversion happen and what exchange rate is used?