Part of the issue is that double entry accounting was designed for the
describing of things AFTER they
had already happened. Its a great system but now when it comes to
budgeting - - - well you are
working on describing future events.
Here everything gets converted to my 'home' currency - - - and I
purchase in at least 2 others.
For forecasting - - - part of the rub is going to be exchange
variations - - - trying to account
for those - - - that's going to be a lot of work.
I find that the credit cards will list the amount in the currency you
purchased in first followed
by your exchange rate and then what you paid in your 'home' currency -
- - - dunno if it will
help - - - just treat your foreign cash as another credit card and
convert your transactions.
That's more work but I've used that for my record keeping (but not for
budgeting!!).
Dunno if that helps.
Regards