Reporting in Project Currency

We are using multi-currencies and our projects are either managed in USD, GBP, EUR or JPY. This works well, apart from when we have to report.

When I create a custom report, all the rows reported are correctly displayed in the project currency. However, any roll-ups, either in Summary rows, Charts or Highlights are converted to our base currency (GBP). See the attached image for an example.
This makes it pretty useless to report back to customers or account managers.

Is there anyway to control which currency a report uses. Are there any clever workarounds I could use to mimic this. None of the currency functions appear to be available in reports.

Thanks