Belgian Electronic Banking: international payments

Dafke

A customer has the following issue: when they make an international payments file in GBP starting from their Fortis EUR account, the bank uses the GBP account to make the transfer. This bank account is hardly used and doesn't have a balance, so immediately there is an overdraft and a lot of costs are involved.
Lately, they made a payment in SEK, and the bank created automatically an account in SEK and did the payment, again an overdraft and costs...

The customer called the bank to inform what happened and they claim that in the payment file, there is an instruction to use a currency-account instead of the standard EUR account.

Has anyone had the same issue before, and what can be done to prevent this? We already made a small change that in the payment file the currency code '' (blanco) is changed in EUR for designating the customers bank account currency, but this has no effect apparently.

Regards,
dafke