In looking at this thread, Currency conversion while adding Indian bank accounts and loan accounts, a possible solution for his problem has come to mind.
Any FX accounts that can be automated by Tiller could be segregated into their own linked spreadsheet. Then you can create a tab in your main USD Tiller using the googlefinance importxml approach to give you a USD view of these transactions and balances. You can then enter new balances in USD for these as manual accounts and enter groups of transaction from this FX transaction view tab (USD) to the Transaction tab proper. May be too much work…
Anyway, in my case above, I’m not anticipating that Tiller Money will automate much, if any of the XSD transactions.