How to maintain USD$ reporting currency with CAD$ Ledger Currency for FA to have historical costs

We are looking for ways to maintain historical fixed assets costs in USD$ which is a new reporting currency for our current CA functional ledger. Would it make sense to duplicate FA subledger and if so can we mass copy from Corporate book to new Reporting Book in USD$ currency? We had a suggestion from an auditor to "created a second fixed asset sub-ledger, using the tax sub-ledger concept". So either that would be creating a new FA subledger for USD$ reporting or using the Tax Book to create the initial mass copy and then any incremental